I needed another corded mouse and this time around I thought of @PKL@mastodon.social and @pronk@mastodon.social instead of Logitech's shareholders. These guys make open source mice among other open source hardware under the brand Ploopy. You can order one from them, assembled or as a kit, or you could print and build it entirely by yourself.
The mouse itself is pretty great. Coming from a long line of Logitech (MX518/G5/G500/G502), it's a bit larger than what I'm used to but I think I'm getting accustomed to it.
Here's another shot of it:
I've used several trackballs, but they have all been seriously uncomfortable for me and my specific brand of RSI. My current "mouse" is a Steam Controller, but using it one-handed isn't great due to the uneven weight distribution. I also have much better accuracy using a trackpad vs a trackball.
Ideally, I just want a Steam Controller cut in half with a more confortable grip that doesn't dig into my palm.