I'm using Samsung Galaxy Note 10+ Android version 10 & One UI version 2.0 & Adobe Acrobat Reader for Android version 220.127.116.1150.
Everything has been updated until April 7th, 2020.
Whenever I open any PDF file, it will ask me "Open With" and lists the various Apps that can open PDF files, When I choose Adobe Acrobat "Always" and open new PDF files it will again ask me to "Open With".
I can't for some reason choose it as Default for PDF Files.
Reinstalled it again, without any solutions.
The problem started to happen to me since Jan. 2020.
Sorry for the experience. Since it has been a while you posted this issue. Just would like to know if you are still experiencing this? I really don't have much to suggest as you already have tried basic things i could have suggested, to look into this further i would like to know if you are still experiencing this issue, please help me with the following info:
OS version including the build number.
One UI version if you have build version available.