If you set "settings -> general -> import playtime of games in library -> always" playtime will be gathered from Steam, etc. even though the gaming session was not started from within Playnite.
Playnite will then use this playtime for that game.
Unfortunately the gameactivity-plugin does not handle this yet.
Possibilites:
It would be possible to "sync" game stats from other platforms/systems, if a supported gaming library is used. E.g. Steam on the Steam Deck.
Obstacles:
I don't know which metadata is gathered by Playnite when importing. This may differ from library to library. It may be possible, that there is only the absolute playtime and it most likely overwrites the stats within Playnite. In this case it would be possible to calculate the diff from Playnite launch to Playnite launch and import the diff as a single recent game session. Even though its not the most accurate.
If you set "settings -> general -> import playtime of games in library -> always" playtime will be gathered from Steam, etc. even though the gaming session was not started from within Playnite. Playnite will then use this playtime for that game. Unfortunately the gameactivity-plugin does not handle this yet.
Possibilites: It would be possible to "sync" game stats from other platforms/systems, if a supported gaming library is used. E.g. Steam on the Steam Deck.
Obstacles: I don't know which metadata is gathered by Playnite when importing. This may differ from library to library. It may be possible, that there is only the absolute playtime and it most likely overwrites the stats within Playnite. In this case it would be possible to calculate the diff from Playnite launch to Playnite launch and import the diff as a single recent game session. Even though its not the most accurate.