Nothing’s working on ALL shorts, not for long, because google shakes things up semi-frequently to jam shorts down everybody’s throats
To solve it once and for all you’d probably want to extract the length of all displayed videos and hide all that fit within the short’s limits
I have leechblock setup to block:
and that seems to block all viewing of shorts. It doesn't stop their inclusion in playlists/recommendations or on a given channel's page(s). Works for me.