Oldman OSB
Marche USB BSB
Ramza BSB2
OK BSB
Yshtola BSB
You can sub-30 with that. I built a team exactly with those units and did so with zero magicite equipped (so you should do way better with some holy magicite equipped for the passives). Exact team I used based on your screenshot and relics was:
Ramza -- Saint Cross -- BSB2 -- LMR + LM2 -- MakoMight
Onion -- Entrust, Wrath -- no soulbreak -- LMR only -- DrMogTeach
Orlandeau -- Assault Saber -- OSB -- no LM -- +30% w/ sword
Yshtola -- Curada, Protectga -- BSB -- LM1 + LM2 -- GatheringStorm
Marche -- Guardbringer, Divine Cross -- LM1 -- +30% w/ sword
Video:
Here's the actions of the units:
Ramza -- BSB2 on turn 1, then command 1 every round, re-cast BSB2 when Onion gives him a bar
Onion -- Entrust Marche on turn 1, wrath once, Entrust Orlandeau on turn 3, then wrath enough to entrust Ramza so he can re-fresh bsb2
Orlandeau -- Assault Sabre -> OSB -> Assault sabre until OSB is ready, then OSB -> repeat
Yshtola -- Wall RW -> Protectga -> Curada every round, bsb if needed (I didn't need it)
Marche -- USB on turn 1, then Divine Cross -> Guardbringer every turn, refresh USB around 15 seconds
Collect loot. This cleared it in about 24 seconds (skipped all fangs). With some 3* holy magicite to boost dps it should be more like a 20 second clear.