LOL you got the best blissey moveset man. ZH Counters Fighting type and has better DPS as a defender mon, DG Counters Dragon + Fighting type and also DG is a 2 bar move with 100 damage each which is insane for a defense move.
So here's my blissey rating on defense move
ZH/DG ->A
P/DG ->A
P/HB->A (but leaning to B because lack of advantages)
ZH/HB->B
ZH/P->B
P/Psychic-> C
I hope you powered up your blissey rn.