symbol password means aplhanumeric characters that accessible from keyboard
some examples jelly22fi$h $m3llycat a11Black$ !ush3r &ebay.44
d3ltagamm@ !Lov3MyPiano SterlingGmail20.15 BankLogin!3
seed password will take too much time to calculate as it have millions of words versus symbol password around 240 chars
not sure does core wallet allow unicode password now, if true that will count up to 65000 chars more