Hmm...I never thought of Section 31 as being Star Trek XIV, primarily because it wasn't a theatrical release and wasn't marketed as such. Technically, it could be considered Star Trek XIV, but I guess that depends on how many people will call it that. Going forward, it may be a case that Trek movies will be referred to only by their titles or abbreviations, which many are already doing now (TMP, TWOK, Nemesis, ST09, and so on).
That being said, I do consider S31 to be a Star Trek movie, but more of a Paramount+ exclusive, if that makes any sense.