From what I understood the rules to be in your example it would be 2021 only. Georgia uses the rolling 183 rule of a year. As soon as it is triggered you will be liable to pay tax for that tax year. In this case, you are taxed for the whole year of 2021.Also, in case you become resident because you spend there "6 of each 12 months", in which year you are resident. For example let's say you spend in Georgia from 1 October 2020 to 1 May 2021 (7 months in 12, 3 in 2020, 4 in 2021), will you be tax resident in both 2020 and 2021 or only 2021?