My body does not like benching. I had avoided, even denounced, barbell benching for YEARS as it always aggravated my joints and really you are selling yourself short. You appear to be an arm dominant lifter also and doing all your presses with DBs wont help. The angle of your hands and more importantly your elbows relative your body have more freedom with the DBs and will fall into wherever you are most comfortable.
I would readily max out the DBs at the various gyms I’ve attended while barely being able to handle an equivalent weight on the bar, because my triceps and shoulders would do all the work. I’ve been really working at it for less than a year now and Ive almost cleared 315 starting from a paltry 225
Some tips for benching:
Learn the form, and by this I mean learn how to externally rotate and flare out your lats in order to brace your humerus a bit during the eccentric portion. This takes a huge amount of stress off your joints and lets your hold a bit more tension to come back up with. I can tell whether I am going to make my lift by the time the bar is halfway down, and if I dont, its my bicep insertion at my elbow that takes the hit. Or my shoulder.
Leg drive is key, your butt is on the bench, but only as a formality; your weight is on your feet. Walk your feet back as far under your hips as you can while still keeping your heels down, and push out with them as the bar comes up, but also as you let the bar come DOWN. Imagine what happens when people lift the butt up when they struggle.
People do this all the time, they dont know it, but what they are trying to do is put as much force into the contact point where their upper back meets the bench as possible by throwing their bodyweight up. The bench in turn provides a greater normal force which is applied to the bar. Do this, but without lifting your butt up by pushing the floor out with your feet.
Once the bar gets low enough, if your arms are long or you dont have a big arch to your back, your shoulders will go into internal rotation, you may want to stop short of this until you can handle it or set yourself up in a power rack with some rails for backup a little above this point.
Try a suicide grip. I used to tell people we have opposible thumbs for a reason, but sometimes its hard to press off the heel of your hand with your thumb wrapped around the bar. Also, you can ever so slightly turn your hands inward to help with that external rotation. I only press bench with this grip now.
Reverse band presses are amazing. If you have access to thicker bands and a power cage, try these, they really alleviate alot of joint stress while allowing you to use big weights.
The aforementioned DB floor presses are a great recovery move, and I’m unsure why. I used to have big subacrimonal bursitis and these knocked it out somehow. I suspect sorcery. Or a forced scapular positioning.
Your forearms look kinda small, if you use straps to pull with, stop doing that, you need strong wrists.
Also unless you played football or some other sport, you may, like most people lack upper body power. Pin presses from the bottom position may not be joint friendly but they do build power. Bonus points for going against bands on these. Also plyo pushups help, and will surely toughen up your wrists.
Now all that being said you may have to accept the fact that benching may not be the best chest hypertrophy move for you. I used to believe this about myself but I feel like my chest really did take off after I got my bench numbers up, but the jury is still out. Regardless you should do it anyway IMO, but here are some general tips for chest hypertrophy:
I mean really, other than pushes there isnt much else but flys can do some damage. I have always wanted to try DB flys with chains because band tension doesnt sound good for these but I havent had the chance yet. Also:
Stretching against a pump
Tear up the fascia while alot of blood is crammed in there. This has worked well for me in stubborn areas like chest, rectus abs, and most notably CALVES. This can also help build seperation in certain muscles: get a pump going, then grab some cables set high and wide and push your torso forward all spread eagle against them. Make sure to externally rotate, or rather just don’t internally rotate or its a waste of time.
Try these, I’ve dubbed them 99’s
Take 3 different pairs of dumbells in maybe ten lb increments. Do 25 partial presses real fast followed by 8 DEEP flys, then do it again for the next weight with no rest, and then for the last. Thats one set, try for 3. Again the idea is to pump alot of blood into the area then stretch it. I like doing these on incline for that clavicular swole that busts out the wife-beater you wear on chest day.