Yeah...it sucks. Trust me. Nobody in my family or friend group is a diver. I literally walked into a dive shop all by myself on a random Friday after work (in the winter nonetheless...stupid me) and signed up. I'll give you several ideas that I've tried and tell you if it has worked or not. pssst...you know...you could just reach out to me...I'll buddy with you.
Local Dives put on by a shop
The absolute best way to meet potential buddies. See...I told you picking an active shop was more important than your OW instructor. Seriously. Pay the $30 or whatever they charge and go diving. Sign up on every mailing list from every dive shop in the area. The SINGLE best way I've been able to find people to dive with. I have done weekday evening dives with Sea Level Diving at Three Oaks. Weekend dives at Three Oaks, Pearl and Haigh with IID, Dive Right In Scuba and Crystal Blue. And during the winter I do open pool dives with IID @ Marmion Academy.
Oh...and one other thing...if you see a diver standing over by themselves outside of the group looking nervous...walk up and say hi and offer to buddy with them. It takes guts to "just show up" and not know anybody. I've been there, nobody noticed me, and it sucked.
Yes...it works. But it's very awkward and high risk that nobody shows. If you arn't the type to butt into a group and introduce yourself...it's going to be hard. I have been known to just show up on a random Saturday at Three Oaks and see if I can tag along with a random buddy group or a class being led by an instructor I know (I promise to stay out of the way of course). I've been 100% successful...but it was awkward for everyone involved.
Buddy App
It has potential. The only thing keeping it back from being actively used by more than a handful of people is the ability to sync your dives instead of manually logging them. I'm over there if you want to mess around on the platform and see how it works.
No. Possibly hell no. It's like Tatooine in the Star Wars universe. It's the "ass end of space". Certainly register, but be careful when you post as it has the worst of the worst of the scuba community, and they actively participate. Remember...don't argue with asses on the internet...they'll drag you down to their level and beat you with experience. And only trust about 10% of what 90% of the people say on that board. I have found it useful for researching dive trips though.
DiveBuddy Website
I won't even link to it...I signed up. Never got any replies except for fake profiles trying to scam me for Russian brides. Seriously.