And in any case, didn't they lower the reserve requirement to 0 at the start of the pandemic?
Reassigning that advance to another person is how we pay for things with borrowed money.
Once it has been reassigned it called a deposit.
https://www.bankofengland.co.uk/-/media/boe/files/quarterly-...
The more important limits to lending are regulatory capital controls which measure both the asset to liabilities mix but also the credit and interest rate risk of the asset mix and loan to deposit ratio.
The latter is a commonly tracked metric by bank investors and they typically view a ratio of higher than 0.8 with suspicion (down from 0.9 post 2008).
The US banking industry ratio is about .63 right now which is up from a pandemic low of .57 but still down from the pre-pandemic ratio of .75.
That banks were not lending enough was the reason the fed removed the reserve requirement.
Reserves are assets of banks that can only be held by banks. They can't get rid of them in aggregate.
Loans are also assets of banks, and are created against supplied collateral along with the corresponding advance. The amount of reserves a bank has is irrelevant to that operation.