I would actually consider Cabba fairly high tier, his Bardock style damage buffs are too good to pass up when there are heavy hitters like Hit(s), Toppo, and Bergamo. He’s a reliable damage sponge unlike Vados and the team heal/lock in is quite useful. Damage wise he needs to stall for a few counts or use a green card to compare to SS2 Trunks, but if you’re going for a serious blast build you’d probably be using GoD Toppo instead.
For a dedicated rival universe team, I would consider Cabba more essential than Caulifla; even if Cabba isn’t being played the zenkai buffs to Vados/Jiren/God Toppo would be more useful than a reliably strong Hit/Caulifla/Lavender. Cabba is an excellent all rounder as opposed to Caulifla’s one dimensional strike playstyle.
The Vegeta synergy is also underestimated; if you have LF Vegeta but don’t have zenkai SS3, he covers Vegeta’s weaknesses perfectly. SSBE can chain tons of cards in the right circumstances, with Cabba’s buffs he can wipe teams.