A mod based on the R2 boilerplate that just 'disables' the global timer after the charging of the teleporter is complete. This doesn't actually disable it per se, but more accurately stores the time at the event of onTeleporterCharged and loads it after exiting the level.
It's not perfect, but it's extremely lightweight and non-intrusive, and it doesn't break anything. Ping me in the modding Discord if you want anything - The Sojourner