Mac OS Monterey

There are factors:

1 - Like poor Wifi connection

2 - Slow wifi connection

3 - Too many other people downloading at the same time and Apple Severs are overloaded

4 - Software on the computer interfering with the download process including AntiVirus Software

5 - Running behind a VPN which may increase Packet losses causing a corrupt or incomplete download

6 - If via wifi too many Other devices using the wifi at the same time reducing the Bandwidth to your computer. 

7 - Best Results are via Ethernet Cable to Router

your mac is identified as MBA (2020 or later) so if that is correct it's not a compatibility issue. do you have enough storage space? you can need up to ~45GB available to proceed depending on which macOS you are trying to upgrade from. and also are you running any apps that claim to "speed up", "clean up" or "optimize" the mac, or any third party anti-virus apps?