I extended a few months back. My ETS was Aug 2022 now it's Aug 2023. Can I reenlist before my extension ends?

You know who could answer this question without error? Your Career Counselor/Retention NCO. The one you did the extension with. But, usually it's 12-18 months (unless that's changed) prior to established ETS date. So, I would venture a guess that your window will open up around August of next near.

Yes you can reenlist August 2022. Go see your Career Counselor

or should I say at the end of my regular 3yr contract or do I have no other option other than completed the extension?