NO TIME LIMIT residence permit UK

Good afternoon friends

I have a question regarding ( No time limit UK visa ).

My Aunt used to have INDEFINATE LEAVE TO ENTER ( ILE ) visa initially which she changed into NO TIME LIMIT visa after coming to UK. Now she has got biometric residence permit with No time limit visa on it. My aunt left UK on 15 july 2019. she could not come back to UK before 15 july 2021. she is still back home and now planning to come back to UK. Now technically she is out of UK for more than 2 years.

What happens in this situation?
Her visa, will it be lapsed?
will she be able to come back to UK?
if she can come back then under what circumstances?
if she cant then what are the solutions?
Could you please explain it to me fully. Thank you.

(Note: My aunt where she is at the moment (back home ) was in red list countries before and still in red list.)

Her ILR has lapsed now. So she cannot come back as she can be refused entry. She must apply for the returning resident visa and prove that she has strong ties to the UK in order for her ILR to be reinstated.

https://www.gov.uk/returning-resident-visa
https://www.gov.uk/government/publicati ... -residents

Thank you