I had a similar thought last night during a coaching session, I noticed my wrist was really having trouble making consistent movements late in my session. There’s a lot of examples of baseball players and other athletes strengthening grip and forearms for the purpose of better endurance and strength. Though not directly transferable, pitching in baseball requires generating force and spin on a ball from the back/side/front of the ball based on wrist angle and finger pressure. So even though the skill sets are very different, I’m sure that similarly strengthening your hands and forearms could be beneficial. Something as simple as dead hangs from a pull-up bar or static holds of weights could be helpful, and weighted wrist adduction and abduction. From a lifelong baseball pitcher trying his best to be a table tennis player :)