are there any ways to make raijin vs ring master not hopeless?
It's not hopeless, you just gotta be patient, work your way in and don't her get away with nothing. She jumps DB2, duck rings, block the mid one if she AMPs it and put Quick Charge up, you will have time to block if she sends a ring.
Once you have quick charge active, chip damage becomes insignificant. You can duck the regular rings, but gotta stay alert because the orbital drop is an overhead and will hit if you are crouch blocking.
Saving meter for Discharge is really key here and you can store it really easily, just block rings and orbital drops. Then you have a 6f answer to most of her stuff.
Don't try to zone her, don't use DB4 at all, you will lose on the trades because her projectile does more damage than yours. The only situation I might use DB4, with quick charge, is when I get a DF2 or BF3, to tag her if she tries do send a ring out.
Against any zoner, when you walk them to a corner they'll want to get out, so be on the lookout for forward rolls or jumps out of the corner. Keep them in the corner with your tools.
I have positive win rate vs Sonja and doing the above works. You just have to be really chilled and be, extremely, patient. Block and walk, get quick charge up, and move towards her.
Best of luck!