cultBgone ... I've been thinking about your OP for a while ... there are no meetups here, even though it's the largest city ion the East Coast of Canada ...
After my divorce at 29 (from my 'worldly' husband), I was so lonely and had no friends (being a born-in and also severely abused child/teen). and absolutely zero social skills. Books were my only friends. Total Social Reject would have described me to a "T". Make friends? How? Really, I had not a clue! So my doctor made a few suggestions, as my depression and loneliness was really getting to a crisis point.
I made some great friends when I volunteered with Earth Festival. That was only about 6 weeks of the occasional meeting, and then the weekend Festival. What a great time, and as we all had a shared passion, much bonding took place. Hahaha, they used to call me 'The AntiChrist', once they knew my JW background, and my atheist anarchist philosophies.
If you love music, there may be a local jazz , blues or other kind of festival in your area. That is a short-time commitment ... at the Atlantic Jazz Festival, you can volunteer to work as little as one shift ... and you get to meet lots of folk. As a volunteer and not an organizer, ANY time you give is appreciated, whether it be for security, information desk, you get the drift.
Volunteering to assist people (hospital, nursing home, youth-at-risk shelter) was more of a commitment, at another time of my life. But you know what I mean, as you have volunteer experience already. The festival volunteering is much more carefree, and doesn't require as much commitment, as your life is so busy right now.
Another way to meet new people, is through common interests or clubs. I''ve wanted to learn to play bridge for years, as the poster Midwich Cuckoo could tell you (yes, I'm STILL procrastinating on that!), so will be looking for a bridge club next winter. Also, if you like darts or pool, bowling? There is most likely a 'for-fun' league that you could join ,,, one night a week, during the fall/sinter months into early spring tournaments. That can be a great way to meet new folks.
Also, and don't laugh! I have never done this, but I know a few people (of both genders) who are in their early seniorhood (late 50s. 60s) who LOVE to play BINGO, and have a great social evening there. I don't gamble at all, which is why I've never done it, but sounds like a LOT of fun.