Step 9

you have come this far, meaning you have gotten through the basics of cryptography.
this will get harder and harder, more than you might have ever imagined.
i will give you a very small amount of hints, if any, past this point.

2 [DYHB] 5 [AEDO]

7 [WSTG] 3 [MJVU]

convert to a base, then shift by the amount