If they were to do it, I would prefer a full remake, similar to the new Resident Evil games (same moments but modern gameplay) as a kind of trial run for UE5 before Halo 7.
At this point, Xbox seems like it's moving towards a multiplatform thing anyway, with Sea of Thieves and three others moving to PS5 and Switch. Whether that's a good idea or not, I have no idea, but it seems like there's been wheels set in motion. And while I'm wary of leaks and rumors, that journalist accurately predicted which Xbox games were going multiplatform, and there have been rumors of Game Pass being Xbox's big focus rather than hardware for a while.
I enjoy the original CE, but if they wanted to launch on PS5, modernizing the gameplay and artstyle would probably be more appealing to non-Halo fans as you mentioned. While Infinite has its share of problems, the art style does feel like a modern Reach/CE and the gameplay appeals to a modern audience. As to why we haven't had more ODST or 3 Anniversary, I honestly don't know. We'll see what happens with all of the rumors in due time, but I figured this would be a fun topic of discussion.
