Only boxoffice.com (which is boxofficepro.com) does the "Long Range Forecast" as far as I am aware. Brad from BoxOfficeMojo, Gitesh from BoxOfficeGuru, Mendelson from Forbes and the like do not. Gavin Feng (for the Chinese market) is fairly new. I do remember BoxOfficeMojo doing a pre-summer article in 2014 enumerating the films that could potentially join the Billion Dollar Club. DOFP was one of them...
Here's boxoffice.com's long range forecast for Apocalypse. As I've mentioned in a previous post I don't know how they could've come up with that number. Singer, Kinberg et al knew Apocalypse was in trouble. They knew the awareness of the picture was so low they had to take drastic measures, up to and including lifting the embargo on the reviews to get the word out that an X-men movie was coming out, not caring if the reviews would actually be good or bad.
For another example of a long range forecast from this franchise, here's their take on
Logan. $7Mil difference...not bad a prediction for being 2 months out. Other recent examples from that site are Captain Marvel's $160 projection vs. $153 actual; Shazam!'s $45 vs $53.
So glass half full, Dark Phoenix might go up to $53-55Mil opening weekend? But that's with Shazam!'s 91% Certified Fresh Tomatometer rating.