Hey guys I need some advice on improving my bench. I look pretty fit but man do I feel downright embarrassed when it's chest day. 1 plate feels like nothin to me but if I toss another 10lbs on each side I struggle to do 10 reps... and I've been stuck like this for what feels like ages.

I generally put my middle fingers on the indent in the bar so I guess I use a fairly wide grip, elbows are at 45 degrees. Can't seem to progress bros what should I do?