I find that in the latest Material Symbols (v4.0.0) there are many codepoints that do not render (e.g. show as a box with an X in it), for instance:
account_circle_full

add_shortcut_to_drive

amp_error

authenticator

bluenote

At first I thought it was just the ones in the nnn
block but it isn't that. I tried using the WOFF2 and also the TrueType versions.