I personally probably wouldn't, but I'm not you and your dog is not my dog. I understand your frustration (more than one of my cats have had bladder problems that caused them to pee outside of the box) but it also sounds like you may not actually be ready to say goodbye yet.
Most vets would advise making a list of your dog's favorite things. If he's still able to enjoy those things then he still has quality of life. It sounds like the main issue here is your quality of life (it's no fun always being upset with your pet because you are constantly cleaning up after him).
What kind of diapers are you using? I imagine he's too small for human diapers so I'm guessing doggy diapers. Have you tried different brands to see if maybe the fit may be better or worse? Are you using disposable diapers or washable? Have you tried using doggie pants over the diaper. There are
"escape proof" dog diaper designs out there (you're noy the only one struggling to keep a diaper on their dog, I can assure you). What about a belly band? Is the diaper falling off or is he doing something to remove it?
Is he constantly dripping or leaving puddles because he can't hold it to the door? If it's the latter, is expressing his bladder a couple times/day an option for you? Is there a reason you can't restrict his access to the house at large when someone isn't available to directly supervise to make sure the diaper stays on?
I wish you luck in your decision. Caring for a pet with incontinence can be daunting and exhausting, I know. One of my german shepherds developed degenerative myelopathy and slowly lost use of his back end. I never thought I would ever be willing to manually express a dog's bladder, but his quality of life wasn't yet poor enough for me to seek euthanasia. So I expressed his bladder (mostly for my convenience, he could pee on his own but he was also leaking so an emptier bladder meant less mess). By the time his qol decreased to the point of euthanasia I was starting to feel really guilty about considering it. I started to doubt if he really was trying to tell me it was time or if I was just so tired of all the intense care he required. In the end I was relieved when someone outside the family mentioned that he didn't seem his usual happy self because it wasn't just me being burnt out leading me to choose euthanasia. But even if it had been, it still would not have been the "wrong" or a "bad" choice. Burnout is very real and your quality of life is important too.