The team drop mechanism is extremely unreasonable

A high-value ticket used on a team with a simultaneously high-rarity aura will yield returns far exceeding solo play while saving five high-value tickets, which is extremely unreasonable. Teaming up means six people's skill damage, and the boss's HP increases sixfold, which is a fair offset, but the reduced ticket consumption multiplier has no negative buff to offset it, which is extremely unreasonable. The bonus from rarity gloves accumulates in the prize pool, and the powerful shield also accumulates in the prize pool. The increased drop quantity from teaming up also has no negative buff to offset it. The increased drop quantity from teaming up should be removed. Items in the dungeon should not be determined by the number of people in the team but rather by the difficulty and quantity of monsters. With the current team mechanism, it’s just trash.

Yes. For solo players, a 6‑man team only bears one‑sixth of the entry cost while receiving bonus rewards on top of that. Coupled with script‑aided multi‑accounting, the unfairness becomes even worse.

What if they kept it as it is for Campaign, but had the group bonus modifiers fall off a bit going from T1-T15 maps?

Yes