Geez… Project managers are forbidden from making work estimates- they only get to collect them.
They don’t get to argue estimates either. They can ask questions to gain understanding but the estimates are the estimates.
Wearing an architect or chief engineer hat is sometimes more fun because you get to call bullshit on dumb estimates like “4 to 5 weeks to model a table with 7 fields, with 2 of them being PK, FK” like GTFO we can model it in the next 5 minutes if I talk slowly.