When all else fails, read the instructions.

Generally, you are eligible to claim the recovery rebate credit if in 2020 you were a U.S. citizen or U.S. resident alien, weren't a dependent of another taxpayer, and have a valid social security number. This includes someone who died in 2020, if you are preparing a return for that person. Use the Recovery
Rebate Credit Worksheet to figure the credit, if any, you can claim.

Form 1040 Instructions, Page 56, bottom of third column.