You need to increase volume to get stronger
At some point you can't add any more weight fast enough to create enough stimulus
So you have to train for longer
Whether it's longer training sessions or more training sessions
Generally the people that don't train for long do so very often and vice-versa
My sessions are currently under an hour but I do this 6x a week and it's pretty much non-stop lifting. Finish the set, change the plates, swig of water then the next set... If I took 5 minutes between sets lol I'd be training at least half an hour longer. This is just me explaining what I do