For most Android devices, Open Camera is a good option for manual control. The Camera2 API setting will need to be turned on to have all the controls, and reading the documentation on the site is advisable.
Some of the Xiaomi smartphones have camera framework restrictions that basically lock all the good features to their stock camera app, preventing 3rd party apps from using them.
Try Opencamera. If it's possible to record 4k60 outside the stock app, that should let you do it.
Yeah I could not find a working version either.
I use Open Camera now and it basically works for most things I want to use it for, and is much faster than the built in Moto software. https://opencamera.org.uk/
Disable noise reduction algorithm if you haven't already done so. I found that the default algorithm on my phone introduces a lot of image artifacts which become visible when zoomed in. You can also try different algorithm settings in "Processing settings" to see which one gives better results for your device.
I also have enabled display grid and horizon level indicator. It doesn't affect image quality, but helps to achieve good composition without crooked horizon lines.
You might also take a look at this page which describes available settings.
The version on F-Droid is just behind a couple versions.
F-Droid is on Version 1.47.3 (2019/10/20) while the play store version is on Version 1.48.1 (2020/05/02)
https://opencamera.org.uk/history.html
As you can see, switching between multiple camera's was added in 1.48.