Yep, lots of different ways to get jacked. That means if you couldn't care less about strength, you can do pretty much any decent exercise that targets the muscle(s) you want to grow in a very wide rep range. Most people want a combination of both size and strength, so you can just do some sets of 5-10 if you aren't already. If you want to have a strong deadlift or squat or whatever, you should train that movement. Not as complicated as fitness social media people want to make it seem: train for what you want.
I don't think this is true. I've been following a fairly standard progression on several of the standard exercises over the last year and half. I've seen steady progression on leg press, which is a strongly stabilized and isolated exercise. I saw the same rate of initial progression on squats but then it dropped off and I haven't really seen any progression for six months.
The issue is stability. I have to provide the stability for squats. The machine gives me stability for leg press. I won't get the stability I need for further progression, at least not at an optimal rate, just from squatting. I need to do complementary exercises.