What happens if my tax returns are still pending and remain that way and the final date to file them arrives? someone who has had the same thing happen to them.

[VolvoGirl]

What do you mean pending and final date to file?  They won't be pending until you efile them.  You have until Oct 15, 2024 to efile a current year return.   Did you efile them?   Even if you file after April 15 any tax due has to be paid by April 15.  Oh, and you have 3 years to file if you have a refund.