For the case of Improvement examination, as you are a boards student of 2021, It was clearly mentioned by CBSE that if a student who have appeared for the boards examination in 2021 and have been declared passed and still want to go for improvement examination, then the improvement examination result will be counted as a final result. So your final result is the result in which you have RT.

For the official notification stating the clause you may visit the link below:

https://www.cbse.gov.in/cbsenew/documents/PERMITTING%20STUDENTS%20FOR%20IMPROVEMENT%20OF%20PERFORMANCE%20IN%20COMPARTME.pdf

I hope this answer helps. All the very best for your future endeavors!