In which scenario is RMC better than Sunday?

I’ve been tinkering around with my Mega Chungus Herta teams and I’m currently using my Sunday with her, are RMC’s True DMG buffs better than Sunday’s buffs in some scenarios? If so when and how?

I’m not very big in theory crafting and crunching numbers blah blah blah, so I would just like to have some outside opinions! Thanks!