Delay With Tax Return Question

Hi, I am one of the unfortunate people who the IRS has not yet issued a 2020 tax refund. I have the following questions:

1- If they issue interest with refund what happens if I file the 2021 return before 4/15?

2- Obviously I won't be able to claim the interest on the 2021 return because I don't know the amount

3- Will I have to file an amended return for 2021?

So crazy that I cannot get an update or status on my refund. Tried to but was on hold for over 3 hours and then got disconnected. Thanks for any guidance you can provide.