Game logs out every 5 minutes after connecting

Thanks for trying the usual network steps already.

The next thing to try is a full local reset for FC 26 and the EA App, along with a graphics reset:

1. Close FC 26, the EA App, and Steam ( based on your platform) 
2. Delete this folder: %localappdata%\EA SPORTS FC 26
3. Repair or reinstall both FC 26 and the EA App.
4. Start the game again with graphics set to Auto, not forced to Low.
5. Set Crowd Quality to Medium and restart the game.
6. If you launch through Steam, open the EA App first before starting FC 26.

One more test you can try:
Temporarily disable Windows Defender Firewall in Advanced Security and check if the 5-minute logout still happens. Turn it back on right after the test.