Before I go off an write something myself, many things we open from our apps are HTTP/S URLs and they go straight to the browser. On Android, it's possible to assign apps to certain domains. I know I could write a script to do the same in linux, but my question is if there is a solution that already does this.
For those who don't know how, here's a superuser page that explains how to handle custom protocols.
This is what I use for now to open videos directly in mpv instead of a browser
~/bin/open-http.sh
#!/usr/bin/env bash
set -eu
# install with `xdg-mime default http-handler.desktop x-scheme-handler/http`
# `xdg-mime default http-handler.desktop x-scheme-handler/https`
# is https and supported by yt-dlp
if [[ "$1" == "https://"* ]] && yt-dlp --simulate "$1" ; then
exec mpv "$1"
else
librewolf "$1"
fi
http-handler.desktop
[Desktop Entry]
Comment=
Exec=~/bin/open-http.sh %u
MimeType=x-scheme-handler/https;
Name=HTTP Scheme Handler
NoDisplay=false
Path=
PrefersNonDefaultGPU=false
StartupNotify=true
Terminal=false
TerminalOptions=
Type=Application
X-KDE-SubstituteUID=false
X-KDE-Username=
A GUI or just config file would be great.
You're not going to like this answer - there's a bunch of different ways depending on the app(s) and the desktop environment. The Arch wiki goes over it in detail: https://wiki.archlinux.org/title/Default_applications
I would guess that focusing on the XDG spec and covering Gnome, KDE and Xfce (Xfce can be replaced with anything else like Cinnamon that comes with Mint, "non Gnome or KDE") is the best plan of attack for what matters to 80%+ of the population.
The above said, it wasn't hard to find a project using XDG and a JSON mapping file (basically your idea fleshed out in python) to get where you want to go if XDG is enough: https://github.com/JonTheNiceGuy/usbrowser