While it is axiomatic that no one can love us more than God, it is an interesting whether it is possible for God to love us more or better. To understand this question we will look at it from two angles: by comparing omnibenevolence to omnipotence and by looking at the idea of the Best of all Possible Worlds.
Now according to the standard definition of omnipotence it refers to God’s being able to realise/actualise any possible state of affairs. However, what is interesting about this definition is that it merely refers to what God could possibly do and not what he actually does. He could, for example, make talking donkeys, and he has done so once in salvation history. However, omnipotence doesn’t require God to actually make talking donkeys, it only means that he could.
Is omnibenevolence like omnipotence in that it only refers to the idea that God *could* love anyone without limit but doesn’t entail that he actually does so? Remember, omnipotence means that God could make anything, he could make talking dolphins or flying elephants, it does not however means that he has to actually do it. If omnibenevolence was like omnipotence, then it suggests that omnibenevolence merely means that God could potentially love anyone without limit but it does not mean that he does so.
To motivate this analogy we can look at the concept of the best of all possible worlds first popularized by Leibniz. The best of all possible world refers to the idea that the actual world is the best of all possible worlds, and it is not possible for God to have created a better world. It is easy, as such, to draw a straight line from this idea to the idea that God could not possibly love us more or better as we are already living in the best possible world.
There are however two objections against the idea of the best of all possible worlds: (1) it curtails the freedom of God in that it entails a form of necessisariantism and leads to modal collapse. What this means is that whatever is, is necessary, everything in this world is determined “in se”, by itself, there is simply no contingency or possible alternatives, from our will and decisions to the movement of the particles, everything is fitted the best way possible. God could not have possibly done otherwise, he could not have created otherwise, in fact he would even necessarily have to create (if our world is the best of all possible worlds than it would necessarily have to be better than the “null” world, a world where he doesn’t create at all, so God is compelled to create, he has no choice on the matter). Thus, while at least the Calvinist God has a choice in the sort of world he wants to create, or even to create at all, the Leibnizian God is more like a platonic form which mechanically emanates creation, he has no choice in the matter or in what form or sort of world he wants to create as it is the “best of all possible world” and God does what’s best. This will entail that there’s no freewill or contingency, etc.
The second objection was articulated by the philosopher Daniel Howard Snyder in his papers Is Theism Compatible with Gratuitous Evil and How an Unsurpassable Being Can Create a Surpassable World. Gratuitous evil refers to evils which are “pointless” and isn’t necessary for some greater good. In those papers, taking a leaf from Peter Van Inwagen, Snyder argues that to suppose that gratuitous evil is incompatible with theism will entail the idea that there is a “minimum” amount of evil necessary to realise some good. But there is no such minimum amount of evil necessary for some good, no magic number or calculus of the amount of evil necessary for some good. It would be like saying that if God wants an impressively tall prophet sent to Israel there is a minimum height such a prophet must be. There is no such minimum height, just as there is no such minimum evil. It is obvious from this argument how we can connect to the idea that God could have created a world where he could love more or possibly do better and there is no such world where he has to love a precise amount or volume.
In his other paper, Snyder argues that it is logically compatible for God to create a “surpassable world”, a world which could be better. Imagine if God were to arrange all the possible worlds he could create in a linear order of goodness. He could exclude worlds which fail some preconditions, e.g. worlds where people suffer for all eternity (yes, I’m an annihilationist), worlds where there are people who never experience any joy, e.g. all aborted children will go to heaven, etc, etc. However, even after excluding worlds which do not meet these preconditions, there are still infinitely many possible worlds which God could create, each surpassing another in order of goodness. There is no reason why God could not simply spin a wheel to just arbitrarily pick one to actualise, and there is no reason why it would be incompatible with divine omnibenevolence for God to have created a world while there are other better worlds where he could have loved more or better.
As such, it seems to me that it simply isn’t the case that omnibenevolence means that God could not possibly love us more or better. Omnibenevolence refers to the divine *capacity* to love, but it does not necessarily entail God *actually* loving us to the “best” or maximal extent, because there is no such maximal extent. Omnibenevolence does not entail that God has to realise all possible goods to everyone, and it is compatible with divine omnibenevolence to not realise some such goods to some, or even to all.
God’s love is boundless, he could always love us more, without limit. But in this finite world and this finite creation, the way his love is actualised is finite, his benefits are confined to the limits of this world. While this world will be subsumed into the boundless new creation and the life everlasting, this new creation and life everlasting doesn’t blast all of God’s infinite life in one go, it is an endless succession of finite gifts for us as we journey without end into God’s infinite life. So we can, across time, always be loved more and more. The damned, whatever transitory benefits or gifts they have received from God in this life, that will be the extent of God’s love for them as they return to dust. God is not obliged to “love them more” and whatever comforts or joys they have received in this life is simply the extent of love God wills to give. How much love from God we receive, in this life or the next, is simply a matter of arbitrary divine choice, there is no “best” amount of love we are to receive from God.
Two quick points of interest: (1) Do you think that the definition of omniscience adds additional color here? It seems like some people would say omniscience means that God knows the truth value of all propositions, but other people say that God knows only all knowable propositions (I think I'm sympathetic to the latter but only if it's defined correctly and this way of framing things is certainly subject to abuse). Do you have a particular way of thinking about omniscience that bears on this discussion?
(2) Not sure if you're familiar, but Peter Geach has a fascinating and quite persuasive paper arguing that God is not actually omnipotent because the concept of omnipotence is incoherent; we should instead refer to God as Almighty: https://www.cambridge.org/core/services/aop-cambridge-core/content/view/30F24F3C3453EC0D00CBD1698DC8A16C/S0031819100060381a.pdf/omnipotence.pdf
(Let me know if you have trouble accessing and I can send you the PDF)