So far Switzerland and Spain has the Android 11 update on their SM-N976B 5G devices. I'll use Switzerland as an estimation.
Last year Switzerland got Android 10 update on 23/12/2019 and UK got it on 06/01/2020, so UK gets the update about 15 days later.
Switzerland got the One UI 3 Android 11 beta on 29/12/2020, if we add the same 15 day delay as last year that would be 12/01/2021.
So even though us Note10+ 5G users didn't get access to the One UI 3 beta programme despite the community manager saying so, hopefully we get the stable official update around the 12th-15th of January 2021 if everything goes to plan!
Edit: Baltic and Romania got the update on the 6th Jan, total of 4 countries have it now.
If we don't get the stable within two weeks from the release date in Switzerland I'll consider changing phone which isn't from Samsung soon and go with one that is more reliable and in which you can expect maximum competency. I can't believe that a £1200 phone is not treated in a high standard and being considered as an old flagship, this is freaking ridiculous.
I would do that as well but as of now it's useless, the update it's just around the corner and we need a little bit of patience. I'd do that only if my phone one day will be forgotten as the s8 series and s9 series phones (which is a shame as they're still great phones), in that case it's worth cracking em. I used to crack them back in 2018 and I must say that I was really happy as I didn't have to rely on Samsung.