The Thunderstore Mod manager sadly only works on Windows. Luckily It isn’t the only mod manager.
There is also the (open source) mod manager r2modman. It works great on Linux and since it has an Appimage, it can easily be installed on the Steam deck as well. It was originally intended for risk of rain, but works with rounds as well.
This mod Manager also has a exe if you want to use it on a windows system as your mod manager
On the steam deck, you have to go in the desktop mode to install it. After the initial process you can add the program to steam to make it accessible via the steam deck ui. (I don’t have one, so I cant tell how to do that)
2. setup rounds mods and have fun.
1. Search “r2modmanplus github releases” in the browser. **Make sure to include the plus since the version without the plus is outdated**
2. Click on the result “Releases · ebkr/r2modmanPlus · GitHub”
3. download the Appimage file in the list under the assets menu
4. open the file manager.
5. Go to downloads.
6. move the Appimage to the desktop.
7. Launch the file and the Mod manager launches
2. Click on “Select profile”
3. tab on online
4. Install mods
5. click on “play with mods” and have fun 🙂
Thanks to LeSnake[GER] for his great guide, all credit to his effort. you can also read the original guide from Steam Community. enjoy the game.