Here’s the scenario, you have a saved password in Winbox for the admin user and you can sign in, but you don’t know what the password is.
There are tons of posts about recovering Mikrotik passwords if you have an Address.cdb file, but unfortunately those only apply to older versions of Winbox.
The best thing to do is log into Winbox with your saved credentials and create a new user with Group: full.
Then reset the admin password and log in. For safety, log into the web interface so you don’t accidentally burn your saved Winbox password.