I want to back up my files on my phone (redmi note 9s).

when I tap on ''back up'', it shows "Can't back up items when backup password is on. Turn off backup password", then I have 2 options: "cancel" or "settings", and then it shows another two options: "change backup password" or "turn off backup password".
logicly, i would like to turn off the backup password to let the backup start, but then it asking me to type  my current full password, and I forgot it.
I don't even knew that I have a password like this, I usually write my passwords on a little notebook.
please, can you help me with that,somehow?