Regarding the OP, there is a sort of continuua of “there’s no way that’s possible” in omnimaxdom.
The most ironclad of the things God can’t do are the things that I call logically impossible, of which 100% of them are along the lines of making pi=7 and 2+2=5. These things can’t be done because the terms “pi”, “=”, “7”, “2”, “+”, and “5” all have arbitrary meanings, and if you try to change those meanings you just end up inventing a new arbitrary system without anybody seriously thinking anything actually changed. Like, I can declare that 1+1=10, but defining a binary system doesn’t change normal mathematics a bit. So god is free to redefine math to his heart’s content and it literally wouldn’t have any effect at all.
This hurdle can be overcome by simply saying that omnipotence doesn’t require God to be able to effect these things.
The next two most difficult hurdles for God to overcome are about tied for difficulty. The first of them is if you decide that his omnipotence requires him to have free will. If it does, then it collides smack with his own ability to predict the future. There are only a few ways to reconcile this: nix the free will (for everyone), or cripple the foresight. Some people try to slip by by saying that god allows free will by choosing not to predict our futures, but this doesn’t work because the problem is that in any universe with free will prediction couldn’t be possible period, which removes God’s choice in the matter. Plus of course there are the predictions that have been attributed to him.
In my opinion the best way to reconcile this situation is to declare that our universe is deterministic but God’s extrauniversal environment is not - or at least, not sufficiently so that he could predict it. This destroys all human free will, but leaves god his, and allows him to make predictions about us.
The second tied-for-second most difficult hurdle for God to overcome is that God is the POE, the Problem Of Evil. Typically the POE is answered with ‘mysterious ways’ and similar incoherent handwaving, but such answers stem from a misunderstanding of the Problem, which is that, by definition, an even halfway omnipotent omniscient god wouldn’t have to get mysterious - and if he were benevolent, he would be morally bound not to, since it’s clearly resulting in a lot of suffering which is, by the definition of omnipotence, completely unnecessary.
If one wants to avoid logical incoherence, there are actually only three main ways to get around the POE, which correspond to nerfing one of the three pillars of omnipotence: The god could be ignorant of our problems, the god could be weak or bound by unbreakable rules that prevent him from aiding us, or the god could actually be indifferent to our suffering or actively evil. Of these, the second option is most preferred in practice, and the first and third are typically dismissed out of hand (despite there being obvious biblical support for the third). Specifically, the god is frequently said to be bound by some peculiar laws of justice or something which restrict him from just forgiving us for free the way Jesus often did. (I wll add that free will is also often cited here, but such arguments are always logically incoherent, without fail.)
The next famous anti-omnipotence argument is the “unliftable rock” argument, but that can easily be sidestepped by noting the difference between things in the universe and things without. One model for a god that gets past the three above critera is the ‘simulation’ god, who can be described as having ultimate power over our universe, but not necessarily having any special power in his own universe that exists outside of it and contains it. The thing to note here is whether you require the god to have omnipotence over the metauniverse of supernature, or if you’re happy if he just has control over the simulation. This matters because if he is omnipotent in the meta universe, he can create a rock he can’t lift - by weakening himself to the point that he is no longer omnipotent, and is unable to either move the rock or restore his strength. He could even weaken himself so much that the unliftable rock could be in the simulation; it could be an Unmodifiable Variable that he has locked himself out of altering. If he can’t remove his own omnipotence, of course, he’s unable to make a rock in the simulation that he can’t move. But on the upside it means he’ll still be omnipotent next week, so choose your preferred outcome, I guess.
Beyond that, anything regarding the physical laws of the universe is kind of in the ‘liftable rock’ territory - if God can change the fundamental rules of the universe, if he can swap out the constants and variables and algorithms underlying the simlation and do so with localized and controlled effect, then that pretty much throws open the doors - miracles become easy and the physical laws are his plaything. Entropy? No problem! He’ll just reset the variables. He’ll reverse gravity and redefine energy itself if that’s what it takes. Parting the waters is a serious cakewalk; he can as easily move the entire rest of the universe a mile to the left so that the stationary Israelites end up on the other coast without moving.
And in fact, omnibenevolence requires him to do so rather than parting the sea and drowning egyptians in the resulting trap. In many ways, even though the POE is not the most logically ironclad point (that’s reserved for 2+2=5), the POE remains the most argumentively compelling, because there’s a whole lot of concrete real world around providing constant examples that omnibenevolence isn’t hapening. So while in once sense nothing is physically impossible for an omnimax god, in practical terms a whole lot of world is physically impossible for him, because it’s physically real in a way that he could not logically allow if he existed.