Sure--but it could be more efficient. I don't care for "5ER" because "ER" does not have a conventional meaning. "5.5e," on the other hand, clearly draws on the conventional meaning. But I would not be upset if they consistently called it that, it just would not be to my preference.
Instead, they keep loudly insisting it is "2024 D&D." I have about the same feeling toward this as I do toward the naming of the game which preceded DOOM Eternal. That is, it is just called "DOOM." Now, don't get me wrong, I think that that game is great (which is very weird for me, I'm not normally much one for DOOM-style games)--but it adds unnecessary confusion. The industry has seemingly collectively agreed to call it "DOOM (2016)", but this is clearly awkward and less-than-desirable. It would have been better if they'd stuck with the original name (DOOM 4) or picked a subtitle to distinguish it (such as DOOM Reborn or the like). Naturally, I would have preferred the simplicity of a numbered entry, since that's really what it is (there are even internal references to the "third era" and such which clearly call out prior games in the series, indicating the Doomguy has traversed space and time and in some way "been" every version the player has played.) But I would have accepted at least a subtitle, especially given it will soon be flanked by both a sequel and an upcoming prequel, DOOM: The Dark Ages.
It just seems really really clear to me that WotC is avoiding a clearer, simpler, more specific name because they're afraid of the implications the audience will draw from that name. I genuinely do not believe that anyone on the team actually prefers this nomenclature over something simpler and more consistent with the game's history.