#Mastodon and the #Fediverse activity will continue to decline until the following things get fixed: (TL:DR: they wont):

1. Algorithms: The general public wants the content to come to them. They don't want to comb through their chronological timeline to find posts they are interested in.
#Bluesky solved this with their custom feeds. They are transparent and can be personalized by the end users.

2. New user friendliness: Most potential new users probably already give up when they are prompted to pick a server. In comparison on Bluesky and #Threads, you download the app, sign up, done.

3. Federation is flawed: Unless you are on the biggest instance, you will not get threads with all replies. Multiple of the same answers are given to questions and the same jokes are told because they can't see the replies from other people. As a result the fediverse feels more dead than it actually is. So either join mastodon.social or accept incomplete federation.

4. Opt-out, not opt-in: Fediverse is opt-out by design unless you run in allowlist mode. If you posted to the public then you already opted-out. It can be viewed by anyone. It can and will be scrapped. It's out of your control. That's why various other settings exist like followers-only or direct messages exist.
#BridgyFed should have been opt-out, but no, your solution was to harass, insult and threaten the dev.