"People who sent the application by post or submitted it through the application office lose the opportunity to submit another application for temporary residence in person, despite having booked an appointment." There is nothing in the regulations about applications sent by ePuap

No, you should not submit a notification for already submitted applications.

The application form is addressed only to foreigners who did not use alternative methods of submitting an application (post office, office, ePUAP).
We would like to remind you here that if your legal stay in Poland ends and you have not received a deadline for submitting the application in person, you should send the completed application to both MOS and inPOL via the office, by post or via ePUAP.