Hi!
Is there a way to modify playtime.play_time_seconds with this mod/LUA command?

not sure what playtime.play_time_seconds is?

There is game.tick and game.ticks_played, which are read-only, so no, this mod cannot edit that.
But there is also game.reset_time_played() which can reset game.ticks_played.

game.tick cant be reset afaik, and its getting difficult, if you hit the max tick and let it roll over.
-> https://forums.factorio.com/viewtopic.php?p=560436

But you can use to get into editor without losing achievements to attempt the proposed fix with this mod.