I offer this with some trepidation as I an known not to be a painter, but its so good and I have never heard of it before and I felt it may be helpful to others.
link
I hasten to add I have no commercial connection with this lot.
I found out about this gadget from a friend who helps to run the UK charity Modelling for Hero's. It aims to provide a venue for uniformed members (military, police etc.) to have somewhere to go and some therapy with friends in a similar position.
A new guy turned up with this gadget that had been given him as by another charity as a way of stabilizing his hand tremors.
My friend who is a keen 1/35 scale modeler was taken immediately and bought one and found it very helpful. On that basis I bought one, having just put my hand on it and decided it did steady even my hand.
I have now used mine and yes it does steady your hand really well.
Wrist rests work but limit where you put your hands. This works at least as well but you can position your hand to where you want it.
Now this came from China, not a good place for US members to get stuff post Tariffs but there may be a US version somewhere. I have put it here as I have never seen it before and something like it may help older modelers like me or others with problems to paint easier.