IMO you should disclose (and it is a disclosure, not a disclaimer) your employer at the top, because it makes the rest of your comment something nearer to marketing copy than user review.
Ive never heard of this startup before, now they're all over this thread. Do you reckon they made this whole thread for marketing purposes? OP is a pretty anonymous user.
I already dislike them now & hopefully never have to use them. Someone else posted Tiddlywiki which is an amazing open-source program, suggest everyone at least check it out. It changed my life. I obviously have no stake in it, so why doubt me? No disclaimer necessary.
I've seen Notion mentioned often on HN, and after giving it a try I'd recommend to at least look into it to see for yourself.