Make sure that your system has python3 installed, otherwise the script will most likely fail.
Now run my script, then download my _agent.js from anonymfile.com/84jO/agent.js and put it into your /home/YourUserName/Frida folder. After that navigate there and run ./launch-server.sh in your terminal. Open up another terminal in the same directory and enter ./inject.sh already, but don’t press enter yet. Then startup steam and quickly execute the previously prepared ./inject.sh
That’s it, good luck and enjoy :) If something’s unclear feel free to reach out, and I know injecting it is annoying but I just can’t be bothered to make yet another script to inject it fully automatically just yet