My experience is very similar to yours :
I'm 44, played in originals bands for 11ish years - that finished a decade ago.
Since then I've been playing at home, learning bits & pieces & working through the grades material.
Earlier this year, I was asked to run the open mic night at my local bar, and ever since, I've been playing nearly every week.
During that time I've met lots of musicians - some good, some not so good - but have had offers to join existing bands on bass. None were right for me, so I decided to ask some of the other musicians if they fancied doing something.
First rehearsal tomorrow!
My experience might not work for you, but you never know who you'll meet at open mic nights.
Good luck with everything 👍