Makes me think Azulath may be right on the 1 mo marketing window if they're firing up in June. It's a bit conspiracy of me, but July has virtually no competition and if they're going to try to be tongue in cheek about it; Independence Day is July 4th... I would argue that 2 months is still the case,.. it's hard to say given Baldur's Gate 3 comes out then but it's also been in early access for years so they don't have much to surprise people with anymore.
Personally I think mid-July to late August is a decent time frame.
Don't get me wrong, BG3 is a game I'm looking forward to so much. Been looking forward to it for decades in fact since I played BG2 when it came out in 2000. If I leave my own bias out of it though, I don't think BG3 is such a huge release.
It's not going to bring the numbers or dominate everything the way Diablo 4 or Starfield will. The genre alone isn't as popular. And, of course, as you've pointed out, it's been in early access for so long, most of the hype train already chooed chooed by. I can see CDPR seeing that 1/1.5 month window as an opportunity. If it's not, then, I doubt it'll be before October.