those I had a conversation with insisted on using the word "new" on those aspects of protection
Who is "those". Don't tell me you have contacts in the Scene - even if you do, I won't believe you. :P
CDX cracked them before and could do that again, but they'll require even more work, to the extent of even writing some emus up from scratch, and there's stuff that involves software engineering to crack a game like Gears 5.
Well, it goes without saying that Gears 5 will eventually get cracked. RELOADED was an Arxan "specialist", if they were around like they were (even as late as 2017) we'd probably see it cracked already. Rewriting an emu for something such as Xbox Live isn't really too hard - as I said, the main difficulty is in the multiplayer, which they won't bother with, since it's not their job to enable multiplayer functionality in a cracked version, although such things have been done outside the Scene by Voksi, Goldberg, etc. to Steam games. In fact, back in the day, cracked server patches were common in the Scene, when dedicated servers were the norm - but now that most multiplayer games rely on a centralized server or P2P protocol, cracked multiplayer is quite rarer than it used to be, and tools for it are (almost) never found in the Scene, although STEAMPUNKS did some interesting things with Sniper Elite 4's dedicated server. And I doubt that Arxan is now as difficult as Denuvo, although I've never tried to seriously crack either myself.
btw even Epic Games Store DRM seems to regularly update between a set of releases, it's not hard though, but if you haven't noticed, the time CDX take to crack an EGS DRM release tends to sometimes increase, Tetris Effect took a full day, WRC 8 some 4 hours, etc.
The API is randomly implemented per-game, such as Steam's was back in its first days (some NFOs from 2004-2008 categorize Steam as "custom" protection, in fact). This obviously requires CODEX to update their emu per-game. If the EGS doesn't go under (one hopes it will, although as long as Fortnite remains a big thing I doubt it will) you'll eventually see the API fleshed out and standardized.