Please help, how can i downgrade from monterey to big sur?

Maybe I am misunderstanding, but an OS (which is software) has nothing to do with the hardware (ports on your device), here are the specs/ports for an M1:

https://support.apple.com/kb/SP824?locale=en_US

Depending on what you are trying to plug in, a different adapter may do the trick?

You need the Trusted Backup you created before you began the upgrade process, because...

...the only way an older version of MacOS will install on a Mac is if you ERASE everything on the drive, leaving no trace of the newer version and deleting ALL of your files.

If you did not create such a backup, please post back for additional guidance.

any solutions to downgrade to Big Sur without losing my files?

thanks before...

No. It can be done, but it's a bit more complex than if you had a Big Sur backup.

You can create one or more backups now, and make sure they contain all the stuff you want to keep.

Then ERASE the entire DRIVE, by Physical device, not just the MacOS Volume.

Then install Big Sur from Recovery.

The on first run, restore only your User account(s) from the Trusted backup.