Hi!
Yours is a very common problem. If your mouse is an Apple Magic Mouse, most users have solved it in three ways. The first is to disconnect and reconnect the mouse. To do this, open Settings, then click Bluetooth, press the "i" next to your mouse and press "Dissociate this device". Then reconnect the mouse by selecting it from the Bluetooth settings.
The second method consists in disconnecting the mouse from the computer (as I described above) and reconnecting it manually via cable. To do this, take any Apple Lightning to USB-C cable and connect it to your mouse and one of the two Thunderbolt 4 ports of your MacBook Air M1 on the left side of your computer. At this point, unlock your computer and agree to whatever the device asks, then stop your Mac and leave the mouse connected for a few minutes. Then take it off.
If the problem persists, try adjusting the mouse speed as follows:
1) Open Your Settings
2) Open the "Mouse" menu
3) In the "Point and click" menu, move the "Pointer Speed" stick to the right
I hope I helped you!