I think (hope) that you've got this wrong.
I'm not an accountant; someone tell me if I figure this incorrectly.
I believe the refundability of this incentive has nothing to do with your refund or withholdings through the year. It only matters that you've paid at least $7500 tax.
Here's an example using made-up numbers:
You make $100k in 2022. Your employer takes out (withholds), say, $15k for federal taxes on your paychecks.
But you make some charitable donations, have a kid, paid student loan interest, etc. and reduced your tax liability. When you figure your taxes next spring, you find that you only owed $10k in taxes for the year. Therefore you'll be getting a $5k refund!
However,
you still paid 10k in taxes even though you got a refund. So the $7500 EV credit is something you can get. You'll get a $12500 check from the IRS.
If you had a job that doesn't withhold taxes (perhaps you're an independent contractor), you do your taxes the same, find out that you owe $10k and have to mail them a check. Now the EV cuts that down to $2500.
If you had no job and didn't make enough money to owe taxes, or you made so many donations that you reduced your taxes-owed (AKA "Liability") below $7500, that's the situation when you cannot take the EV credit.
Liability just refers to the taxes you owe on your income, based on your tax bracket and any deductions you can claim---
not the balance owed or due at the end of the year. That's just a correction on imprecise withholding.
Edit to answer your first stated question: No I don't think that's actually the case.