Struggling with friendships.

I knew that lockdown would make me stir crazy so chose to do a free genealogy course with FutureLearn and started on my family tree. I became addicted and the winter passed in a flash. I am looking for a choir to join for this winter and a country dance class for OH and me in the evenings.
I hope you find something which works for you.

Have you tried the meetup app?
Their are people who meet up for social nights, pub meals, board games, philosophy - in short; everything.

How about seeing if there is a local book group that meets in the evenings ,there are more likely to be people there who are at work during the day. Then you could suggest a meeting for coffee when you get friendly.
It is difficult I found this when we moved on early retirement the retired people in our village had long been retired and the few I found have left because of your reason. Try the local town library there might be a local history group or some voluntary work that needs help. There used to be something called "the House wifes Register", that had different groups within it but I don't know if it still exists.
Or do it the way it was done when my Dd's were small, someone put a note through my door asking who would like to form a morning coffee group where turns would be taken in each other's houses it was called the "cabbage" club. My DD found a local cafe that ran a coffee morning for women on maternity leave and she made lots of friends her age. Hope this helps it is a peculiar feeling being isolated and surrounded by people who need help rather than friendship.

I was going to say volunteering, but see you are already doing that.

Can you find any 'solo' absorbing winter hobbies? Make yourself a rag rug, knit rugs for Battersea, do a 'diamond' picture, get all your photos uploaded onto a usb pen? Think of things that you could do alone, that would give you pleasure?

Perhaps a big part of the problem is that the people you would prefer to befriend are still working full time and don’t have time for involvement in the activities you mention, so those you meet are mainly older and retired? I’m not sure there’s a solution to that, other than being in paid work yourself and socialising with colleagues.