That's not good @DannyG6 !
If a soft reboot by turning your phone Off.
Remove any relevant sd card.
Hook upto a computer and try using Samsung Smartswitch to see if that kick starts it.
If you do get into it put it into Safe Mode which disables your downloaded app's but let's your stock app's keep working. If the issues stop then this highlights a downloaded app as the possible issue. Come out of Safe Mode and start deleting your most recent downloaded app's one at a time until it stops.
and if that does not help then you may have to try a hard reset however this has the potential to delete any saved data in the phone.
Hard Reset samsung-galaxy-note-20
Most Samsung Experience Stores and Samsung Service Centres are closed due to the pandemic but if available where you live you could try a doorstep Samsung repair service option.
I wish you all the best with this.
Daily Driver > Samsung Galaxy s²² Ultra 256Gb in Phantom Black.
The advice I offer is my own and does not represent Samsung’s position.
I'm here to help. " This is the way. "
it is a possible that the under oled screen have been damaged because amoled and olde screens are very very fragile so they can be easily be damaged
🤬Today after 4 months of using the Samsung Galaxy note 20 ULTRA black screen without a working touch and fingerprint sensor (charged, did not fall, I did not flood it, always protected like an eye in the head). Unable to unlock, cannot connect to PC, DEX does not work, cannot be backed up. Due to the fact that it is a TOP model, it only works for 4 months !!! 🤬
Experienced the same issue while browsing on phone. The screen went black. Tried all possible solutions and didn't work. Have to replace the LCD as per tech support. This is so disappointing considering it is a flagship phone!
Exact same problem on mine. Wasted all day on it, then it magically started working. Now it is broken again. I have had every samsung flagship, but i think i will switch to xiaomi. I'm so upset by wasting probably 20 hours on this now. As well as not having a phone after spending $1400 on it and it didn't last a year. I've barely even taken it outside, much less dropped it.