Afaik, event type is generated by log insight when ingested. So not at source. Also the event type is only unqie to your installation.
Normally when filters are used its to include something. I have not used it to exclude stuff.
Also could you provide an example of what you dont want getting into log insight?p
this ended up being a syntax error -_-
the corrected form is:
blacklist=event_type == "v4_f39b2ea6", event_type == "v4_3fd251c1"