Just to clarify does this "frozen" carryover loss from 2019/past years need reported anywhere on the 2020 return?
No. That's why I stressed the importance of a physical hard copy of your 2019 tax return.
if the rental does return for 2021 are you able to confirm the carryover loss returns and is allowed to be deducted up to $25,000 along with the rental activity (assuming other qualifications are met to did this).
It's allowed, provided you meet the criteria in 2021... and it would be very uncommon for you to not meet the criteria. Exactly how you handle it, depends on to many factors to cover at this time. You'll just deal with it, when the time comes.
