Times for things like "age of the universe" are usually given as "cosmic time" for this reason. If it's about a specific object (e.g. "how long until a day on Earth lasts 25 hours") it's usually given in "proper time" for that object. Other observers/reference frames may perceive time differently, but in the normal relativistic sense rather than a "it all needs to wind itself back up to be equal in the end" sense.

The local reference frame (which is what matters for proton decay) doesn't see an outside world moving slower or faster depending on how much mass is around it to any significant degree until you start adding a lot of mass very close around.