Source 2013 Singleplayer Crashes Immediately When Launched [Linux]

Hello, I did some testing recently which required me to launch into a Source 2013 Singleplayer mod on Linux, however when I booted up the mod, it seemingly crashed instantly with no error message. When attempting to directly open Source SDK Base 2013 Singleplayer with the upcoming beta branch installed, the same crashing behaviour happened. This testing was done on my Steam Deck with SteamOS installed on it, which I factory reset twice and the issue still persists at the time of writing.

The only piece of useful information I have is when trying to run hl2.sh or hl2_linux, I get the message "Failed to load the launcher" with nothing else that could be used to determine the source of the crash, even when attempting to debug a mod via Visual Studio Code. Is anybody else experiencing this issue? What could be done to resolve it? I would really appreciate some advice! One thing to note is that I haven't experienced this behaviour with Source 2013 Multiplayer mods, Half-Life 2 or Portal, it looks like only Source 2013 Singleplayer mods are affected.

I've also created a short YouTube video which shows the crashing behaviour in action and the things I have already tried to stop this from happening: https://youtu.be/yMRdxg6Bdo8

Start by reproducing the crash on SteamOS with Source SDK Base 2013 Singleplayer on the beta branch, using hl2.sh or hl2_linux. Read the launch output showing “Failed to load the launcher” and compare it with the reported working Multiplayer, Half-Life 2, and Portal launches. Done means identifying the cause and documenting or fixing the Singleplayer launch failure.