EDIT: It looks like someone will just have to add support for EGLStreams to continue supporting NVIDIA in LE10/K19.
That's pure silliness, if I understand it correctly. Half of the emulators included in RR require some sort of GPU horsepower. Imagine Dolphin without NVIDIA. I'm working on Steam support primarily for gaming with LE/Kodi. I get it that NVIDIA hardware support is beyond frustrating on Linux (Torvalds gave it the correct gesture). However, I will either be forking LE or switching to running Kodi on Arch Linux if that is the case because I, like so many others, have sunk so much $$$ into NVIDIA hardware over the years, and they really do make the best hardware. Le sigh. I'll need to find the right tree to bark up.
Well if it comes to Linux & retrogaming just use an AMD GPU or APU. For everything else I nowadays use mooglight & stream games from my workstation which makes more sense than having more than one capable system.
I'm pretty sure nobody of the Kodi devs will include EGLStreams to Kodi unless some other dude will do this & I can totally understand why because all other GPU devs focus afaik on GBM.
LibreELEC has it's own focus & agenda of course they focus on HTPC usage which means playing media & Retroplayer runs almost all low end consoles up to the PSX now which means no need for faster GPUs. If you switch over to Arch it's a whole different story because that's a usual Linux distro which is not using a read only filesystem and means you won't get a predictable & preconfigured system.
In the end it's all about ideology and somewhat stubbornness. Nvidia refuses to deliver OSS drivers & use common standards. Wayland doesn't care much about all features X11 had in the past because for desktop usage it's useless. Kodi devs don't want to maintain several backends the same time and some features like HDR need GBM iirc.
So all in all... either drop Nvidia GPUs or move to Arch or stick to the LE9 branch as long as it's possible. Personally I don't think that HDR is a feature that is important enough to drop compat and several other features. I updated & fixed the wayland backend a while ago and this could be a way to go if it would be possible for Kodi to adjust refresh rates. Nvidia drivers come with wayland libs so this could work too. If vanilla LE is dropping all Nvidia or X11 support and there will be no fully working wayland you end up with a 400$+ Generic HTPC which has basically the same featureset as a 30$ TV box or RPi. Both can run Kodi and that's it, so I don't see the value in having a full sized media center if that's the future...