Hi Jerry. Doing Bench press with 50 lb dumbells is pretty darn impressive. That would be the equivalent to about a 150 lb barbell. And reps? The max, if we were stupid enough to risk it, would be up there.
So you are achieving a great training effect and impelling the body to get its muscle mass up.
Your press, with multiple sets of 5 with 75 lb, is more than i can do.
And your pulldowns, again, is much more than my current capability.
To improve the way you want to, perhaps my strategy might help. I suck at improving strength. Many years of trying to add weight to the bar didn't help at all. Putting more weight on the bar meant i just couldn't lift it. And muscles didn't grow.
Then i hit on my current strategy, that worked pretty well when i was younger, and even now inches upward.
I would list the sets and weights and reps for my workout, before i did it.
And each exercise would list an additional rep with its top weight. If you are doing 5 reps, it's easier to do a sixth, than lifting 5 lbs more.
Most of the time i made the target, and did not have to cross off the entry.
As the reps accumulated, i was then able to increase the weights and drop the reps back, before coming on again.
Nowadays my progress is agonizingly slow, and i am way back from what i did last year, pre covid. But, hey! What you gunna do?