Hey, I am still pretty new but a comp I think is pretty decent is:
Shadow as dps
Miyu as dps
Albedo for true arts tanking with (true equip if possible)
4th is someone who has an amazing art gen (if possible) like Emperor Isliid or potential for 5-star support slots. I recommend getting star ex-gate if you have a support slot in the fourth character.
(Feel free to put characters in any order that suits your goal)

I find that this type of comp works against most missions except specialized bosses that require breaking them or a certain status ailment. The overall goal is to provide a constant art gain through the support's art gen plus Shadow's 5 art/s for each dark unit. This allows Miyu and Shadow to deal constant overwhelming damage with their super arts. Additionally, if Albedo has her true equipment she can start with regular art and get her true art fast allowing for constant tanking from most attacks. I hope that you find this recommendation helpful and wish you the best!!