In theory, there is anything you want, if you have the immense computing power.
I read JNandez is working on that area, in that case, you would be paying 100 or so per month by using it. He has some theory for it also.
I don't use his PLO solver, preferring the PLO's Vision as it gives a general view that I add into my own strategy style partly, in the long run, and my style is build from NLH GTO, adjusted to PLO, and from top sources partly, and lately Vison, but I am only adding it very slowly during the years.
What you get fast with the Vision (or partly if you know NLH GTO) is how often to check and bet -- position, flop -- and with what strength of hands, and I don't see a reason why one can't adjust the GTO math to PLO5 also and then use the Vision (also) further to add to it structure and more details (from PLO).
The solver solutions start to become less and less accurate the further the hand goes, as your opponents are not playing like a solver and one needs to understand the math instead -- the easiest way to play semi-GTO.
Preflop, a bit tighter than in PLO, common sense, considering the 4 cards, possibly even open-limping some hands? Air is not as good in PLO5 on the flop even heads up, so the values go up, and what one bets as the upper range, go up as well, though free cards can be dangerous so need to think how safe it is to check, and then add some mix for balance. What you check or bet, common adjustments from PLO. PLO5 isn't really the place to start at, and at one time it was NLH, just for learning GTO, and still partly is from the math part.
The turn completes anything, is a danger card in some way, some PLO concepts for sure. The river is mostly about the bluff factors, or values too, and one needs to adjust a bit when it comes to blockers, I suppose.
Solvers can be a messy thing if one doesn't understand GTO math, and then one needs to make it practical also, and so group it more simply. Maybe we get a Vision for PLO5 at some point, to see more accurate ranges, as I am not sure I have time for looking hands one by one.
I am not finished with PLO for many years to come, so not in hurry for PLO5 either, nor do I think it is needed at this point, using whatever ideas I get from PLO.
The biggest issue is getting worthy games to play to practice PLO5, as they are too loose at limits one should practice it at.
There was a fast-table at ******* (PPPoker etc) that in theory could be tighter, but they removed it (probably too low limit to be tight there anyway). And yes, they offer mobile only here, and as vertical where the cards are smaller -- ideal for PLO5, lol.
If gets more popular, the sites will offer it as fast-poker also, but I am not sure that will become the case, as even at GG, I saw under mid-limits at non-busy times to be much less popular, and it has not been offered as zoom at Stars. Maybe they get requests, and would not be the first time or the fifth time they have implemented something suggested.
Solvers for loose games, no. There are simple guides for that; pick any poker form, pretty much so, but some PLO5 articles. Relatively bigger pairs, and as the opponents play too many of them, especially a lone/dry top2 goes down in value, and there could be a big draw more often, and there are less poor flops; any flop has more two pairs and sets, and straights.
