This is a misunderstanding of GTO....its just not true. GTO poker is a way to play where you become unexploitable. Also, nobody PLAYS GTO poker. People try to emulate GTO, but it is not possible to play. It's kinda like "what would Jesus do". You cannot emulate Jesus, only try (hypothetically, of course).
Basically, what "unexploitable" means is your opponent will be indifferent to decisions against you, because you made the perfect play (every time) that makes them not know what to do. It does NOT mean playing break even poker. The only way a perfect GTO player loses long run is if "it" is playing against 8 other GTO playing entities. Otherwise, the non-GTO players will make their mistakes and lose (long term) to the GTO player(s). It also means that (it) will play a mixture of different ways for the same scenario so that it is less predictable. for example, on a dry flop with an A in a 3 bet pot, it might recommend betting 67% and checking 33% of the time. The computers have played this spot so many times they have figured out the most optimal mixture of times to bet and check to extract the most value from AK flopping an A on a dry board. That's what GTO is about....what to do and how much for MAXIMUM VALUE (if you bet it out every time, players could theoretically over fold to you here....thereby EXPLOITING your tendency to bet always in this spot).
Getting back to playing GTO...you can try to play GTO strategies, which is a winning strategy then deviate from GTO when you find out the way to best extract value based on the villain. HOWEVER, if you don't have a fucking clue where GTO is, you really cannot stray from GTO to become exploitative, now can you?
Exploitable poker is figuring out where your opponents weaknesses are, then adjusting to extract MORE value than if you played strictly GTO. In your case, with opponents calling preflop with way too many hands, your optimal exploitation would be to raise/3 bet more frequently against their range. If players are more tight, your exploitation would be to fold more to their raises and be more wary of when they call you. GTO is the base from where you should be moving your game left or right....based on your exact opponent. IT IS NOT break even poker.