You could simplify it a lot.

Let's say the river is 33322

IP range is AA, KK, A5, K5 and Q5

OOP range is KK, QQ (all six combos for each).

Let's say you bet 100% pot as IP with AA for value and some bluffs (you can put KK into the betting range as well to make OOP not call 50/50 of QQ and KK), and OOP calls KK and folds QQ. In this spot you would bluff K5 but check Q5 because K5 reduces the number of calling hands by 50% and Q5 reduces number of folding hands by 50%. A5 doesn't block either and is getting a fold 50% so it's the same EV to check and bluffs.

What is the overall folding frequency when you hold K5? And the same with Q5?

Blockers are fairly high hanging fruit imo, I don't think they're incredibly hard to get an understanding of but I think they often distract people from the more obvious things going on in the hand and cause people to make -EV plays in the name of making "good looking" plays. Blockers are relevant when your opponents are calling close enough to optimal that blocking a few calls will make your bluff +EV but blocking a few folds will make it -EV. This isn't the case in most river spots up to and including against a lot of 500z regs. It's much more important to understand what you're expecting your opponent to get to river and fold to a bet with vs what they get here and call with. Identifying things like, for instance, a range full of hands like pair + draw that will now fold to aggression is much more important than which specific blocker is the most valuable. They are also a natural progression from developing the thought process laid out because once you can imagine roughly what someone will call you can start to think things like "oh a lot of those hands will have x in them, we want to have x ourselves when we bluff" or conversely "a lot of hands they fold will have y in them, we don't want to have y ourselves".

So basically build the GTO process out of the exploitative one, first get really familiar with working out whether they will call enough/too much/too little then start honing in on the times that you think they're calling enough and start looking to use blockers to shift the balance in those spots.

I see blockers used in the same arguments both for and against bluffing and/or valuing better and I'm just like well most people don't know wtf they are talking about with blockers.

Like if you bluff with missed A high flush draw:

1. dude your blocking his top pair top kicker so less hands that can call, its go good for you to bluff here
2. dude your blocking his flush draws which you want folds so there more hands to call ,dont bluff

If you are going to pick and choose when blockers are good for you and ignore it when its bad for you then you don't understand blockers. So yes its used to justify dumb plays most of the time.