Samsung Galaxy S20 Ultra 5G 16GB RAM 512 storage
U.K. on EE network unbranded CSC code BTU
I signed up and was accepted as I met the Beta criteria, unbranded CSC and in a country Beta testing was being carried out. I then received the first Beta test firmware as soon as Samsung rolled it out for my country. If I recall correctly, it was after Germany and Poland received theirs.
After the last Beta update it was 2 weeks exactly to the stable roll out. As per Samsung's schedule, that should be January 2021. See... https://eu.community.samsung.com/t5/galaxy-s20-fe-galaxy-s20-galaxy/android-11-amp-ui-3-0-stable-rol...
I notice that the Beta roll out started yesterday, 2nd December, in India and Samsung's home country of South Korea for Galaxy S10, Galaxy S10 5G, Galaxy S10+, and the Galaxy S10e. See... https://www.xda-developers.com/samsung-opens-android-11-beta-one-ui-3-0-galaxy-s10-series/
So , now you have to wait for Samsung to roll it out in your country.