Everyone keeps telling me WoT is going to fix this, but I have always been pessimistic on this and I am afraid the only solution is just good old moderated chat groups and forums ... This twitter thing is not viable long term

To be fair, nostr implementation of WoT is somewhat sparse. But a complimentary system wouldn’t hurt.

If you used a client that simply ignored people that are 3 hops away, it would solve almost every annoyance.

how can you moderate an open group that a million bots can join? you need an automated prescreening system

Just like you moderate every forum or discord server or Reddit page or whatever.

In Telegram some public groups have a captcha bot. Every user joins without permission to post by default, the bot posts a captcha along with a link the user can click to open a DM with the bot where they can then send the captcha answer. But that’s a mechanism working on top of another, as telegram account creation requires a phone number. Maybe the best approach is just layering in general.

all these things have prescreening based on phone numbers

All that means is scarcity... You can do the same thing with Email, and let email provider choose their own scarcity. Some may choose phone numbers, some may choose invitation links, some may only host their friends and families... These providers are scarce because DNS names are scarce and so on and so forth. This is why digital identity scarcity is really important