I deal with the same problems. I suggest getting a small vise to hold parts you're working on. This is what I use. I bolted it to a 2 x 6 to provide some heft.
https://www.harborfreight.com/2-3-4-quarter-inch-articulated-vacuum-vise-3311.html
The articulated head let's you position pieces level to dry after gluing or hand painting. When I do precision work, I use both hands, using my left to steady my right. Getting old has it's challenges.