Especially since 2015 when public nash solvers became available that calculate equilibrium strategies across the whole game tree (previously they only did preflop)

I have a blog dedicated to the topic

www.livepokertheory.com

I would stop short of saying it’s more math or more complex than chess though . The math to code a solver is hard but using one to improve at the game is easy. Most top poker pros are not mathematicians nor do they need to be. Poker is also many mixed strategies so often it doesn’t even matter what you do as long as you don’t always do the same thing

But yes it’s both a skill game and a gambling game and currently my primary source of income

This is just not true, you don't need a lot of math to play poker at a top level.