I understand you want to learn GTO, or Game Theory Optimal. I encourage you. I include names associated with GTO and Game Theory writings. I add a caution.
RedChip says, "...no-limit hold'em can be treated and solved like a math problem." Polk says, "The GTO strategy for No Limit Hold’em supposedly exists, but is not yet known by any human or even computer." Woolley says, "It is likely to be many years before a game as complex as full-ring, deep stack, no limit hold-em is fully solved, meaning that the GTO move for every possible situation has not been determined."
I personally view GTO as a theory that presently leans towards writer testimonials, situational game applications and the assumption that the undiscovered actually exists.
GTO reminds me of the Theory of Everything, TOE, as it is referred to by scientists. GTO and TOE are hardly similar, but it’s difficult for me to think of one and not the other. TOE is supposed to be a single theory, that when discovered, will explain everything about the universe. Scientists like Einstein and Hawking failed to discover TOE. That doesn’t mean poker theorists should yield the search for the GTO strategy for NLHE. But, right now, there is no GTO strategy for every possible situation in NLHE anymore than there is a TOE explaining everything in the universe.
Both theories, however desired or promising, assume outcomes that may never be found. Keep this in mind as you study. Best Wishes.