Mid tier equipement are better when unleveled and anyway, event equipement are better than all gacha equipement. Gacha equipements worth only as bond crystal source.

Imho, thebest way to farm lvl100 manyu is 80 stamina Secret Gardens. It give 4 or 5 lvl20/100 manyu and 10 Life Crystal (maybe still 16 if the last week camping is still on). Then 100 stamina daily maps or secret gardens summoned byu manyu keys.
You can do thoses evolution material maps. It summon a lot 80 stamina Secret Garden (30 garden got on 50 runs on these maps).