Im a solid Samsung note series users since note 4, note 5, note 6, that 3 series is the best note series for me compared to note 8, note 9, note 10+ and note 20 ultra 5g...
Anyway here's the issue about my note 20 ultra 5g... Last week it suddenly restart and keep on booting. Until it drains the battery so I charge it fully. When I turn it on it turns normally so I used it for an hour it keeps on booting restarting. So I decided to drain again the battery. But before doing that i also tried to use the power and volume up button simultaneously also the power and volume down to reboot but it didn't work. So when I drains again then fully charged the power it turns normally again so I decided to factory reset the phone. Then it was successful resetting. I didn't use the recovery or restore from backup I only use same account but I skipped the app to be installed. But 2 days after doing the factory reset it still reboot and stuck in the boot up logo...
Sorry to hear you're stuck in a bootloop. Like Bern said - you might have a motherboard issue. Many times, no amount of factory resetting can bring it back to working condition. I hope your visit with the Samsung Service Center yields good results 👌👌
