The pattern brush windows in the 'fun effects' area of 'guided' is only intermittently available. Is there some reason for this? It's an effect I'd like to use and it's annoying when it's not available.
Pattern Brush guided edit mustn't disappear all of a sudden. Could you please capture a screenshot if this happens again? Please share the screenshot here so that we can understand the issue in a better manner.
Meanwhile, you can try resetting the preferences as shared by @Phinny.
Could you please check whether you are navigating to the right location for the Pattern Brush Guided Edit in Photoshop Elements 2020? It appears in Guided Edits > Fun Edits > Pattern Brush Guided Edit.Scroll down in the Fun Edits window if it doesn't appear on current screen.
Thank you to all who replied. I think I discovered the problem. I still had a previous version of PE on my MAC and it was booting up to THAT version which didn't include the pattern brush effect. Once I deleted my older version... THERE IT WAS! 😁