In a post on the Wrestling Observer Forum, Dave Meltzer said that the talks with AEW go back a few months but Bryan did not know where he was going because things mostly depended on if he could work for New Japan Pro Wrestling. The NJPW aspect of the story was also reported months ago in the Wrestling Observer Newsletter.
Meltzer said that he didn't know (and Bryan didn't know) how the talks between WWE President Nick Khan would turn out so Bryan was basically waiting before deciding on whether he would stick with WWE or go elsewhere.
Meltzer said the following in response to a member post, "I had no idea because I didn't know how the Nick Khan talks would turn out. Nobody had an idea. Danielson didn't have an idea. If he didn't have an idea how would I have an idea? I had a very good idea that whoever got the NJPW deal would get him, but even then, it's not like I knew 100 percent. This is one I've explained over and over in detail from the start. It's not a percentage thing. It was 90% whoever got the NJPW deal and 10 percent maybe he'd decide regardless."
Meltzer added that in regards to Bryan that "serious discussions had been going on for months."
Prior to WrestleMania, Bryan may have already known that he was likely going to leave WWE. In April, he told BT Sport that he felt detached before he went out to the ring for the main event at WrestleMania.
Bryan said, "This was weird, I was out there, and it felt like I was detached. It was so strange that before the match started, I got this strange feeling like, 'Oh no, is this what it's like before you die? Am I going to die? Huh, well, OK.' I don't know why or how it happened, but it was unlike anything I've felt while wrestling."
During the same interview, Bryan talked about his contract expiring and figuring out what he wants to do with his life.
h/t to Bleacher Report for the Bryan interview quote.