Agree with WZ. One of my worst ER cases ever was a giant newfie that basically bled out from NSAID-induced ulcers (he got like two doses of carprofen), couldn't get blood into him fast enough. If you already know your pup could have an issue, I'd never look at that as an option again personally. And if you feel you have to, I'd be aggressive with omeprazole, sucralfate, and talk to an IM about misoprostal (the miso is a little controversial, especially as a 'preventative').
Some other options to investigate/talk to your vets about: Assisi loops, PRP and/or stem cell therapy (can be $$$ but I've seen some really good responses in zoo med with stem cells), Librela (acknowledge the risks/talk to your vet, this is controversial and not as well loved as Solensia), continued joint injections if the initial round seemed to help, and surgery/arthroscopy if that's an option financially.
Also just verify that your Adequan regimen is accurate according to the bottle insert. In my experience it's often not given as it is supposed to be and that can affect results.