What version of the Samsung+ app are you using that shows the beta? I'm running 10.21.2.0 on a N950U1 and am not seeing the beta registration option.
I'm also have a N950U1
I just got PIE update in beta program in USA Verizon Unlocked Note 8
Look in the Samsung + and join
Just joined and it's downloading now.
Some tips for others, open Samsung+ & join the beta program, then go to settings and software update on t...
Unzip.... TWRP 2.7.zip and take the recovery.img file and this is and will the file to use with flashify...
Thank you. You're the man...that got my recovery back :)