Xcode sets itself als default application to open markdown files even if prompted not to, apparently at login.

After Xcode broke my git installation for intractable reasons, removing the present git executable from my PATH (there are StackOverflow posts about this dating back to 2017!), which took me hours to figure out, I now have another problem caused by Xcode.

Xcode sets itself as the default application to open a bunch of file types, most importantly for me:

JSON and Markdown.

I repeatedly right-clicked markdown files in Finder, selected "Open with...", then changed "Recommended applications" to "All applications", selected QLMarkdown, which is the application I want to use and which was grayed out for intractable reasons as well, then I checked the box "Always open with".

This works for one session if I'm lucky, but after closing the lid of my MacBook and opening it again the default is already reset to Xcode.

This is not acceptable:

Xcode is a dog-slow application even on an M1 Pro with 32GB of RAM and is absolutely unsuitable to open Markdown files for viewing because it takes ages to start and uses a lot of battery.

I want to keep my defaults and I would very much like Xcode to not break my system settings, as it is a required application to do lots of stuff on macOS.

As far as I am concerned, this is clearly a bug, not even a bug in Xcode but a bug that makes Xcode break other applications, which should be fixed with high priority. Would send this to feedback but first:

Does anyone know a workaround or possible cause for this?

I read something about reinstalling Xcode but honestly that's not something I am willing to invest time in.

I'd prefer to remove it altogether and try to work around that, but it seems Apple wants to make this hard for developers of even non iOS-/macOS applications.

Thanks