I wanted to downgrade Mario odyssey to the version 1.0.0, but when I checked the cartridge the serial number ends with 002, would I still be able to reset?

Unfortunatley, no. In order to downgrade, your serial number would need to end in 000. In your case, the only way to get 1.0 would be to go and buy a 1.0 cartridge.

oof

Rip, thank you though