I updated firmware and RouterOS to latest versions, but every time I try to change the WPA2 Pre-Shared Key and then apply it, when I try to login to my Wifi with the new password it doesn't work, and the default password still applies to the wifi network. Also, I see nothing in Wifi Interfaces and wonder if this is related to the issue.

In webfig menu area there is a hide-password button to see the password as you typed. Also there is a safe mode button that if on when you change the password, you will have to toggle off/on to make changes permanent.

I suppose you have no Wifi in your device, that is the simpler explanation.

What MikroTik unit do you actually use?

Post export config: in a terminal type: export file=blabla hide-sensitive
Copy that into [] brackets.