Most microcontrollers also don’t need wall clock, monotonous time is sufficient. uint32_max counting in seconds gets you 136 years of uptime before the thing wraps which exceeds lifetime, in milliseconds it’s 50 days which is well within the warranty window.
And, no, 64bit time_t is generally not an issue for 32-bit platforms: Those upper bits only get touched once every 136 years. OS vendors did step up and change stuff so everything that gets produced now should be fine. And don’t even start complaining about memory budget while those things are talking json.