I took up the Banjo. I played guitar for 40 yrs, but it became too difficult for me to work the fingers, don't have the strength anymore. When I started the banjo, I didn't play Bluegrass or country, I learned "Old Time" (OT) music from the hills. The style of playing suits my PN perfectly. Its called 'clawhammer'.
The popular theory is that old arthritic people (many of them women) had hands like claws, bent and curled fingers, so this style of playing was developed somewhere around 300 BC or something .
I went to a gathering of OT players one Sunday afternoon, a 'jam' and there were about 15 people there with banjos. 9 of them were women. They played durn good, too.
Anyways, the left hand on the banjo is easily learned and requires little pressure on the fingers. Much easier than guitar or mandolin, or most stringed instruments. The only one that requires less pressure is the violin, which is the least amount of left hand finger pressure I know of.
The right hand strikes the strings with the back of the fingernail on a downward motion, kinda like a downslap or like knocking on a door, fingers kinda curled.
Sounds awkward, but it isn't all that bad. It requires little finger strength, just practice for accuracy.
There's even a website with a clawhammer forum (CH is the recognized term) for ''Old Time' music players (www.banjohangout.org)- but I play mostly 'folk' music using the CH style.
Mebbe this could be a project for you? I dunno, but it keeps me occupied when I'm getting bored or 'cabin fever' set in.