You stopped at one meetup? What are your interests beyond Linux and programming?
Deep dark buried backend stacks in cloud infrastructure, or perhaps control a drone that monitors engineering or construction progress, etc.
There's a challenge there to socially meetup and connect to develop work, a career, or just exchange information.
Social friendships might come out of such pursuits.
(FWiW I'm in W.Australia, > 60, and had an interest in version 0.0 Linux when I was porting Minux to a transputer array and eating popcorn when Tannenbaum and Torvalds were back and forthing on UseNet)
Which is fine, and recognizing that might help you find it. End of the day, having meaningful social connections takes actually being interested in other people, not just a shared external interest, or hobby.
That's a part of why modern male groups break up easier. No more "thing" no more Meetup.
The endless lockdowns destroyed pretty much all of civic society there and the place hasn't recovered, literally everyone I know from that period left after the lockdowns ended.
A creative hobby in which you could apply your programming skills perhaps?
Here's my 2c. Pick an interest that attracts the kind of people you want to spend time with. Immerse yourself in that interest. Go meet people who share that interest. Spend time with them.
Any previous experience with that interest is not necessary - you can be honest and say you're new and learning. People tend to love sharing their interests.
This is where being open minded to new interests can pay off handsomely. If your new interest comes with new friends that you greatly enjoy the company of, you will most likely develop a genuine interest over time as the natural result of those shared positive experiences.
Many of our existing interests are the echoes of positive experiences from our childhoods, and you can use the exact same mechanism to pick up new interests in adulthood.
And conversely if I think hard enough, I can probably come up with something I never had early positive experience with but still pursued because I found it interesting. I'm also very interested in traveling in space, but I definitely don't have any experience, positive or negative, and likely will never gain any. I'd totally join a club that talks about traveling in space in a heartbeat though.
Worst case you're hanging out doing something besides your favorite thing, but you're still hanging out.
You’re not giving anyone much to work with. I honestly can’t imagine only having 2 interests that are related.
Hope you find some joy!
I had a similar issue going to 3d modeling meetups. Surprisingly few in Los Angeles. There's one blender Meetup that comes around maybe once a year and that's it.
It was bad before COVID, but Meetups completely torpedo'd during it. And it has bounced back as much as I thought.
Of course, the party goes bounced right back. More introverted activities, not as much.