This is an FYI if anybody runs into the same issue. Years ago I setup my P1S to connect to my production Wifi on which VLAN my computer was and all worked fine with BambuStudio on Linux (Flatpak). Then two years ago I moved my printer to a IOT VLAN with only internet access. Since I print using the Bambu cloud this all worked fine. Until (I think) version 2.4 of BambuStudio (2.5 same issue). When my printer is connected and I start Bambustudio it sees the printer and I can send print jobs to it, but after a short period of a minute or so it disconnects and says it can no longer connect to the printer. Switching from the prepare tab back to the device tab re-connects the printer, but again after a short while it disconnects again (Bambu handy on my phone kept the connection all the time). This was both using Flatpak or the appimage. After troubleshooting I tried one thing, my computer is wired to the production VLAN but I configured its wifi to connect to the IOT VLAN. Now the connection to the printer was stable. And after removing the wifi connection and had only a connection to the production VLAN it stayed stable. Seems that in the newer versions of Bambustudio (the network plugin maybe ?) needs to have a direct connection once to the printer to keep connected over the Bambu cloud.
Not sure if this is specific for Linux, I don’t use Windows or MAC, but in case you encounter the same issues, this might be one thing to try.