Here's a map of all (known) deep space stations.
You can look up those systems in the Gal Map and see which one is closer.
You can enter any reference location in
EDDB to find the nearest station to you.
I tried entering your location (DRY AUB XZ-Y D7508) as a referecnce, but EDDB doesn't have it. Are you not uploading your data to EDDB?
Nearest station to Sag A* (with repair facilities) is
Polo Harbour @
Boewnst KS-S c20-959, 11,304Ly from Sag A*
(According to EDDB)
https://eddb.io/station?h=has_repair&i=1&r=21276
It's a deep space outpost on the route between the bubble and Colonia. It's a planetary base so you'll need Horizons.
Colonia is almost the same distance away (11,367Ly from Sag A*) so it probably won't make much difference which way you go.