Hello Aspirant ,

You can attempt JEE Mains in 2023 even without repeating  class 12 as a student is allowed to attempt JEE Mains exam for 3 consecutive years starting from the year of passing class 12 (in your case 2021,2022,2023 ) but unfortunately can not attempt JEE Advanced as you are only allowed for two consecutive year (2021,2022) .

I would advice you not to repeat class 12 and attempt JEE Mains in 2023 , get good rank and take admission in a good NIT as this will save your one year .
Hope this helps.