KSP2 probably didn't have any amount of outside playtesters at all during development, despite PD having founded a playtesters group (the Pre-Launch Pioneers) for KSP1 starting with the Making History DLC, because of that notion they enforced to "keep scott manley away from this."
Essentially, they didn't want anyone with preconceived notions of Kerbal to touch or have any opinion on KSP2, and that included choosing not to carry over the playtesters group they had for KSP1 in the long tail
Now, I'm not here to say that was a bad decision but like. Y'know. Obviously it was, everything Take Two enforced on Kerbal 2 was. If you wanted Kerbal 2 to be accessible to the masses you should've taken input from the people who made a career online of making Kerbal 1 accessible to the masses. Literally, where would KSP as a series be without people like Scott Manley who made it approachable.
It's just like how if you wanted to play minecraft in 2011 you had the wiki open in your browser, except to play Kerbal you had Scott Manley videos open, and videos by others like him. All of us in the media group (from which KSP1's Pioneers group was originnaly sourced), essentially, had taken on the burden of making the game approachable to others. it was our job basically to educate people about the game, we couldn't just play it on stream or in our videos we had to be that bridge and that rope ladder to help climb KSP1's impossible learning curve.
And they didn't want any of that anywhere near KSP2 until it bombed in early access and they were suddenly liek "HEY GUYS ITS TIME FOR KSP2'S PIONEERS PROGRAM" as if it wasn't already like, five years too late