The best password or pass-phrase is one that you can’t seem to ever get entered correctly before getting locked out /grin
Three unrelated words separated by spaces is much more difficult to brute-force hack than a single word obscured with numbers and characters. There are plenty of write ups on just this thing. Make it easy on yourself and try it.
For instance, “Child Of The Sixties” could be a great password. If you need a number, change Sixties to 60s. It would take much longer to crack that than say, “IL0v3W005$tock”
It looks harder to crack, but computers don’t think like humans.