I experienced this at first with my ergo, and for me it is currently not an issue. There are some minor issues with some of the super common keys that are in different places (like enter which is currently on my left thumb on my ergo, and right pinkie on normal keyboard).
Starting with my ergo was also very disheartening (for me I went way too extreme with my switches which killed my accuracy for a month), but I love it now.
Not sure about your timeline, but the Naha Create is currently on Kickstarter, and I think might satisfy all these requirements: https://www.kickstarter.com/projects/naya-create/naya-create
In general, I’m not sure how easy it is to have multiple pointing devices? For the example you give of a coarse and fine pointing, the most common solution is to have keys that switch between coarse and fine pointing on a single trackball. I’m not sure if QMK can support two pointing devices at once (without significant customization).
For single pointing devices, I’d check https://bastardkb.com/ . They are also very slick devices, but can get pricy.
HolyKeebs just announced their new keyboards with integrated trackpoints: https://holykeebs.com/pages/trackpoint . Something they do that is really cool is build them into the microcontroller itself, so if your board has the microcontroller in a convenient place, you can add the trackpoint straight to an existing device (already sell it for pimoroni trackballs, trackpoint in Q3). I have a Corne from him with the pimoroni, and I enjoy it, but the pimoroni is not a full mouse replacement for me.