I think not adding new features frequently and keeping everything stable and working in the long-term is also meritorious. Vim is the same on my local machine, on my rpi, and on an Ubuntu 20.04 VM that I use for some proprietary software.

Also, I cannot think of an extension / new feature that makes sense as a part of Vim (if I want something more, I want a lot more. I don't want Vim to do a lot more, for the sake of simplicity and conformity, that's a job for vscode with Vim extension).

At the same time I wouldn't object to someone adding features to this program. But they have to try really hard to convince me to start relying on that feature (I wouldn't, because I would miss it on Ubuntu 20.04 and I will forget how I used to work without that feature).

I tried nvim a few years ago and honestly didn't find anything advantageous there. But since I had `:sh` in muscle memory and it was a bit (very?) different there I gave up on nvim.

I use vim and nvim in parallel, just ask init.nvim to read from ~/.vimrc, all is good

I don't think that will ever happen. They have already diverged in key ways. I'm more than happy with vim9 and where it is going, personally.

I have also switched to nvim, but every release I consider moving back.

Honestly a lot of this is that I hate Lua. With so much of the infrastructure moving in that direction it's basically unavoidable. XDG support was honestly one of the things holding me back; I'm glad that this is finally fixed.

Has neovim settles on a UI yet?

NeoVim tossed significant amounts of legacy code (eg 8.3 filename support) and greatly improved out of the box default configuration. You cannot merge the two without upsetting one camp or the other. Vim wants to continue to be a stable platform that runs on 40 year old hardware. NeoVIM wanted to ditch the cruft that no longer makes applies.