(Mod/Help Request) Offline Protection via Reinforcement

[EndlessOats]

I'd like to make it so reinforced blocks become unbreakable a configurable amount of time after the player who reinforced them logs off a server. I tried to do it without modding but there's nothing like that built into the game, it seems. All I know is HTML from middle school and a little bit of GDScript so I'm basically starting from scratch on modding. Any help appreciated, including letting me pay you to do it for me because I'm lazy