Why my lifts are rather weak I can tell you that:
I started off at 45-50kg bodyweight and never got any instructions whatsoever so I did all my research online. I always went with a friend of mine who didnt knew shit either and then he got a spinal fracture or something like that because of deadlifting wrong, while I was training with him. So I neglected to squat and deadlift because of me being too noob for that (also NO instructor can to this day squat or deadlift properly at my gym, literally an hour ago an instructor was quarter squatting and all other instructors were hyping him up). Then 2 years passed by and I didn’t diet proper till my 3th year hit and I started dirty bulking + crash dieting. That shit didnt work out either so I decided to really study this stuff and since then i’ve been making good gains.
I wished I didn’t had to waste like 2-3 years of trial & error but well, I learned a lot and can help other people that are new to the gym with all the mistakes I made.
Also I don’t think my OHP/Bench Press are that weak, my deadlift & squats just are, but that’s because I never do them. And I do agree Barbell Bench Press isn’t that much of a good mass builder either in terms of what EMG studies show, but my chest is my best genetic. Even when I was 45kg I had some chest forming going on and it doesn’t even matter what I do for it, it just always has good proportional form imo.