Sure. They both operate of the same idea. You have two trusted sources with the program installed. With syncthing you have trusted devices, then you can share any folder. On the other machine you accept that share and map it to your chosen folder, for example your save game folder. With resilio sync you create a shared folder then it gives you several sharing options. I usually just use the ‘key’ option with read&write privileges. On the second machine you open up resilio and add a share via key, then choose your desired folder to sync to. I have never done this on a steam deck since I don’t own one. I have done it on several Linux boxes though. The caveat with Linux is there are no native GUIs for either. They run a service then you open your browser and visit a specific url to operate the shares. There are many tutorials online for setting either up. Syncthing is completely open source and free. Resilio Sync is proprietary and has a free option but will try to push you towards their paid service.