I think this may be something specific to a particular save, I'm trying to see if I can salvage it somehow.

I've been playing a save with AngelBob and a few QoL mods, everything was working fine until yesterday. When I loaded the save, Resource Monitor, along with a couple of other QoL mods as far as I can tell, stopped loading. In the case of Resource Monitor, the button at the top disappeared but I do get a ding when I put a drill on a new site. Weird thing is, starting a new save with the same combination of mods seems to be working fine o_O

Yeah so this might be related to some QoL mod messing with the UI buttons. Right now, they're only created whenever the player is created or the mod is first loaded into a save. This means that the button is simpy gone if it has been removed.

The mod is still working, there's just no way of access the menu when the button is gone.

You might try to load the save without Resource Monitor, save it (don't override the original) and then load that save with Resource Monitor loaded again. I'm not sure right now, but that might trigger the re-creation of the GUI button.