The “ignored” option on the notification settings you have on a user will completely wipe their content locally for you.
^ ignored reply
^ ignored user quote
That is how discord blocks work when the blocked person chats in the same group/server as you. Viewing the blocked user’s content is opt-in.
You also won’t receive notifications from this user. If their behaviour to you is worth a block then it is worth a flag and they are clearly breaking rules by harassing/bothering you, which rule-breaking can be flagged.