The Android 10 update is currently only seeding for the unlocked units in Switzerland, but the rollout should soon expand to other countries where the 5G version of the Note10+ is sold.
The Android 10 update rolling in Switzerland for the Note10+ 5G carries version number N976BXXU1BSLA and comes with the December 2019 Android security. You can expect an update notification on your device in a few days, but if you don't want to wait, you can try checking it manually by heading to the Settings > Software update menu of your smartphone.
If you live in a country other than Switzerland and have got Android 10 on your Note10+ 5G, let us know by sending in a tip through here.
https://www.sammobile.com/samsung/galaxy-note-10-plus/firmware/#SM-N976B Not so I'm afraid. I have an unlocked one in the UK and it is certainly not available here yet.
I believe that by now all the markets have the update, only the carriers are holding it back.
Because it's so many different phones from different manufacturers and different hardware