This particular area behind the main Termini train station is pretty ugly and somewhat run down.
It really isn't a nice area in daytime, and it definitely doesn't feel safe walking around there at night.
I'm surprised Hyatt wants to open a "Regency" branded hotel there...I would have expected a more budget brand such as "centric" to use such a location, and even then it would still be somewhat odd.

Looking at google street view it seems to share a building with an enormous multi story parking garage, and strangely doesn't seem to have a main entrance that a car or taxi can drive up to as its entrance is on a private (closed off) very small road which is part of the "nuovo mercato esquilino." I honestly can't see where the hotel main entrance would be,

Also, as others have already mentioned, a 1 year proposed opening date is pretty optimistic in Italy.
I'm always reminded of the 5 star intercontinental and W-hotel branded hotels which were advertised for years as "coming soon" in the city of Milan (which runs more efficiently than Rome) which wound up both never opening at all.

So I don't expect anything before 2026 at the earliest.