I hadn't heard of mouse arm syndrome, but I did get an ergonomic vertical mouse, and I find it a lot easier on the wrist.

Here is an example: https://www.amazon.in/Logitech-Verti.../dp/B07FNJB8TT

I'm sorry if it shows Amazon India and the price in rupees. My computer seems to be defaulting to that because I'm in India right now.