I made this post a while ago, explaining a lot about learning ZBLL, so it should be really helpful.
But if there's anything else that I didn't explain in the post, I would be more than happy to provide any additional information.
uhh so i am quite confused because i’ve seen people saying to learn COLL as a “stepping stone” to learn full ZBLL. What’s a good way to learn ZBLL efficiently? Should I go straight into learning ZBLLs or should i learn some other alg set first?
Learning COLL as a stepping stone isn't really a great idea from my experience. The only thing you gain from it is recognising the CP (Corner Permutation) but that can be learnt without COLL. Most of the COLL algs are just slower for 2H solving compared to the standard OLL alg, and COLL only really has use in OH where EPLL's are just so much...