Sorry to hear that, I started this thread and I will tell you what fixed it for me.
after the impossible to use beta one experience, I restored to iPad 17, I did not restore data and then updated to iPadOs 18 once again.
that did it for me, beta one was usable without the freezing issue and beta 2 and 3 keep chugging along without the issue.
Yes not a great solution but it worked.