Microsoft now owns Call of Duty so Halo has no obligation to try to make Call of Duty money when they own THE live service game. The problem is Halo will never beat Call of Duty at its own game, it's too slow compared to COD, especially the Black Ops subseries' breakneck combat pace. Nobody is going to abandon COD for Halo, hell, for all the kvetching online people didn't really leave COD for Battlefield. Fucking Fortnite having a Simpsons event showed more player movement across platforms.
It also can't really compete with boomer shooters since so much of the boomer shooter trend is "remember what shooters were like before Halo?" and consciously avoid regenerating health and the two weapon limit.

As it is, Halo is kinda trapped with nowhere to go unless they massively revamp its gameplay. Otherwise it's just catering to the shrinking audience of people that still give a shit about Halo.
Really I think the most financially viable thing outside of just mass porting the games for the hell of it is just selling Master Chief as an operator pack in Call of Duty. He wouldn't even be that out of place with Black Ops 7's future setting since so many characters are already wearing bulky power armor.