I agree completely. The first computerised machine I ever worked on was a photo-typesetter which was entirely keyboard controlled because mice hadn't been invented yet. That machine was serviced every 6 months and the service engineer once told me that the keyboard was such an important part of the system that it should be inside the casing, not outside! So in flight sim the keyboard, mouse and monitor is the right way to do it for me, even more so now that I have an HDR curved monitor which removes the 'fish-eye lens' effect on flat screens in MSFS, and adds 10 FPS believe it or not!
To address the OP's points, I have to agree to some extent - when you start looking under the hood a few of the features of FS2020 are merely 'place-holders' and not many have been significantly updated or replaced so far. It was obviously easier to start from scratch with those, so let's hope that's what they've done with FS2024.