4G and 5G need devices to be synchronized to each other by like 1.5 microseconds or they'll start getting a lot of errors. They do a lot of time division duplexing, so if things are not well synchronized people start talking all over each other.
Now, that's just synchronized with each other, so if the Moon is off by whatever difference in time that's not a problem. It is not like that 4/5G cell is also participating in the same RF environment as cells on Earth.
