I guess it depends on what you're planning doing with NixOS or Aux. I wouldn't use it for anything new and critical. I'd figure out a mitigation strategy if I were relying on it for something critical.
But for experimental purposes, neither option seems like a bad call.
Disinvestment into Python, Flutter, and Dart is a clear signal that those tools are unimportant to Google. I won't be recommending that anyone use Dart or Flutter on new projects.
I wouldn't expect that you could go from zero experience with Neovim/Vim to more efficient than the editor you've been using extensively in less than a month. most of the people that responded here had been using Vim prior to switching. The one that had no prior Vim experience took half a month to get the basics down and be comparable with their prior editor (VScode).
Everything you're after is available, but trying to learn it all at once can be overwhelming as you've been experiencing.
Reinstall a fresh stable version of NeoVim and if you haven't already followed the tutorial, follow it.
Install ripgrep for full, in file, text search for the current (or specified) directory.
Install kickstart.nvim and watch the kickstart.nvim walkthrough video to learn how configuration and plugins work in Neovim. (It also includes a Fuzzy Finder [fzf] that works with ripgrep inside of NeoVim.)
Practice Vim Motions so they become second nature to you. Watch the first 5 videos of The Primeagen's Vim Video Playlist to see the fundamental movements beyond what's in the tutorial. You could use a VSCode extension that replicates Vim Modal Editing with Vim Keybindings to get used to the Vim Motions while you're still using VSCode.
Get familiar with the Neovim User Documentation which han be accessed and navigated with Vim Motions by typing :help while in Normal mode in Neovim
Watch videos on multiword/mulitline editing options with Neovim (Part 1) | (Part 2)
The best chat beginner community for Neovim that I know of is in The Odin Project Discord. There's a Neovim thread in the #odin-general channel there. (Bonus, while you're in the Discord you can help out others trying to learn web development.)
The point is to find your own way by learning from others, not to simply mimic others. Although up front, mimicing what others are doing is a good way to get started.
I try to be positive here on programming.dev but someone gave you an incredibly thoughtful reply and you returned the favor with absolute disrespect. I think the only positive outcome here would be for me to simply block you and encourage others to do the same.
I'm going to throw this out there not being sure how true it is, but I find it interesting to think about.
XMPP is much more widely used than Matrix if you count WhatsApp (Meta/Facebook). ActivityPub is much more widely used than AT Protocol and nostr combined if you count Threads (Meta/Facebook). So reasons why people aren't talking about XMPP include not wanting to recognize that Meta is hugely influential in this space and that most people don't talk about the underlying protocols of the services and tools they're use at all leaving a self selected group of people looking for alternatives with traction that don't depend on Meta. Outside of WhatsApp, there's not a lot of traction with any particular XMPP implementation. And none of the XMPP implementations have a Discord-ish organization of chat rooms that's popular and familiar right now. Matrix has both right now (although I don't think it will ever be more than a small niche in the mobile messaging space).
I'm fine with using Matrix for what it is. There are programming language communities that have been very helpful for me and a number of Lemmy related communities that have been nice to be a part of.
It cuts both ways. Less commercial interest means only hobby level development (which can be high quality, but is typically slow and unpolished for users).
So you can spend your energy on making up the gap between the ease of use of the commercially supported software and the pure volunteer projects or you can have free time for things you're more interested in and jump ship when they squeeze too hard for cash.
Element is the thing that's subpar (to be generous) compared to other chat apps. Element X is better for the features that have been implemented, but the current feature set is very incomplete.
I guess it depends on what you're planning doing with NixOS or Aux. I wouldn't use it for anything new and critical. I'd figure out a mitigation strategy if I were relying on it for something critical.
But for experimental purposes, neither option seems like a bad call.