TexasSolver VS ZippySolver

I use GTO+ which is proprietary.

I just tried this one which works like a charm (just run the exe from the zip in github releases ; even comes pre-loaded with a wide amount of preflop ranges, which seem to come from a previous solve) : https://github.com/bupticybee/TexasSolver

Searching with "poker solver haskell" only seem to show very immature projects.

Texas Solver is a free one. I now of atleast one other free one that also works in the brower ( though with reduced RAM), but sadly forgot its name; if I remember I'll edit.

You're basically trying to program a solver such as GTO+ / Monker / Pio. That's not an easy undertaking. If you really wanna pursue it, learn about counterfactual regret minimization (CFR). If you want your solver to have a reason to exist when the others already exist, try to make it faster than the others (and/or less RAM-intensive). There is room for such improvements, probably by doing what's described in Noam Brown's thesis (which I believe I gave you the link to previously). There was an open-source project ZippySolver that was gonna use Noam Brown's work, but it was abandoned and idk how far along they got. Even just a standalone equivalent of Jesolver would be good; see the papers at the bottom of that page.