Thank you for sharing your story and your reflections here. As you said, while one could still argue if freedom of speech is really at risk with such unexplained Twitter bans (and I'm not saying it is not), it is still a fact that time and effort are lost by the user banned.
For anyone creating content directly on centralised platforms, this is an important wake-up call.
Publishing content primarily on a self-hosted blog / website / newsletter is a good practice. After all, we can always create content on our site and post the link to it later in whatever social media platform we desire. It is also possible to build (and retain!) an audience directly from our blog/newsletter if readers subscribe to it.
As you well pointed out, social media platforms such as Twitter and Stacker News are extremely valuable for content discovery, conversations and moderation (by leveraging the likes, dislikes, etc). But we can mitigate the risk of losing everything by adopting self-hosting of our content at least :)