Sorry if I missed this, but are you using aas?
Have you tried going the other direction? More intensity less volume? A Dorian or DC type of program would put you in the 2-3x a week range but you wouldn't have all those sets. If you're throwing that much weight around and not getting results you're either not targeting the muscle right (form issues) or you're not recovering from the workout. e.g. if you bench press big weight but you cave your chest in or use too narrow of a grip - you'd have big tri's and massive front delts. watch guys with weak pecs but big arms bench and you'll see what I mean. you want your shoulder blades pinched and pinned to the bench.
I'm not exactly a hard gainer but I hit a wall years ago where nothing worked for me. I switched everything to a mish mash of DC/Dorian style training. I take a main exercises (my 3 are decline/incline/inclive db) and I do a set of 12, 10, then a weight I can just hit for a workset of 8. after the 8 I rest for about 8-10 breaths and push out 8 more. if I hit 8 I go for a 3rd set and the following time I'm on that exercise I add weight to the workset. the reps are STRICT - explode up, squeeze at top, 4-5 seconds controlled negative. You should literally not be able to complete 1 more perfect rep at the end. Where I vary from DC is I then go and do an isolation exercise with the same strict form but I utilize higher rep ranges and I hit failure. I group it like DC so I have A and B 1/2/3 but you could easily just group 3 chest days and do it every 3-5 days.
here's my last chest workout to give you an idea
incline smith bench (I list just the weights I put on the bar)
90x12 180x10 290x5 rest 10 seconds 250x6 - rep 7 was failure
i can move way more weight but using my strict rep method is how I was able to make gains.
cable flye machine
drop sets with no rest between sets, to absolute failure starting at 150lbs
in 4/5 days I'll do decline bench with incline ISO press