The Alt+numpad method used to work fine in Flash for Windows, but is broken in Animate. A few versions ago they fixed it not working in the Actions window, but it still doesn't work in the Text tool, where it's needed most. I've reported it, but the more reports the better for something fundamental like this that really should be working.
For reference, some of the most commonly useful codes:
Alt+0145: open single quote
Alt+0146: close single quote
Alt+0147: open double quote
Alt+0148: close double quote
Alt+0149: bullet
Alt+0150: en dash
Alt+0151: em dash