if all our atomic clocks and computers turned off for a day solar system wide, would it ever be possible for us to get on the same timeline again?

like is there a pulsar we can look at and be like "yeah it's been 1238374737 microseconds since we measured this a month ago"

can we measure galactic drift or something and compare it to an old measurement accurately enough?

in this scenario we still have access to old data but no continuity