I am by no means a super technical person, but it's a fact that the instructions provided in the page about how to install league on my steamdeck did not work no matter how hard I tried.

What worked for me was essentially:

1. Install lutris flatpak
2. Download GE's lol-wine version
3. Manually download the league installer from rito's site
4. Manually invoke the downloaded wine executable to run the installer

.var/app/net.lutris.Lutris/data/lutris/runners/wine/lutris-ge-lol-8.7-1-x86_64/bin/wine <installer>

1. Let it install completely(login, download the entire game)

2. Add it as an installed game in lutris.

Boom! A more portable way, no reason to be afraid that the next SteamOS update will break your installation.

You could probably modify the script a bit so that you create a custom wine prefix rather than use the default ~/.wine