OneDrive can automatically pause synchronization when Windows enters battery saver mode or connects to a metered network. Could you please confirm whether you've checked OneDrive > Settings > Sync and backup > Preferences > Pause syncing when this device is in battery saver mode and ensured that option is disabled? Also, does OneDrive display the actual "Syncing paused" message when this happens, or does it simply stop uploading files? Could you share the OneDrive version listed under Settings > About and confirm whether you're using Windows 10 or Windows 11?
Could try resetting the OneDrive synchronization client, which Microsoft recommends for persistent synchronization issues. Press Win + R, enter %localappdata%\Microsoft\OneDrive\onedrive.exe /reset, and press Enter.
If OneDrive does not restart automatically, open it from the Start menu.