Trackball mice a good solution to this problem. I had work on a bed without a table for 2 weeks last year, and a trackball mouse ended up working great (I didn't like using the trackpad, since switching from the keyboard to trackpad on a laptop is fairly uncomfortable if you do it often enough).
Trackpads were a great upgrade to laptops when they happened, even though at the time, excessive moisture screwed up the trackpad, to the point that I needed to have a dime handy to put my finger on for a half hour after getting out of the shower.
(Source: I've used mac portables since the PB 100, including most of the major versions)
Switching from the keyboard to something an inch away is uncomfortable for you, but switching from the keyboard to something a foot away is not? I don't get it.
Additionally, when I'm using it on my lap, the trackpad is basically next to my body, which makes my wrist position a little uncomfortable.
Looking back, I think it's not really the switching, but rather the comfort when using one for a prolonged period, for which I found the trackball easier.
See https://imgur.com/a/qeRQIFD
An offset trackpad would also work, though obviously would be less friendly to lefties.
Because most people don't use vim and mice aren't usable unless you're sitting at a flat surface with the room to hold one. If I'm using my laptop on the couch, a trackpad is probably the best solution. (Trackpoint gave my index finger RSI, when I was was being careful.)