It physically hurts me to say anything in facebook’s defence, but to be fair this is an account centre link to an account config page

I didn’t consider account recovery, that’s a good point. Personally I don’t usually bother with it for anything I want to be private - if I lose it I lose it lol.
It’s still not perfect, but some of the private email hosting providers like proton have email aliases, so you could use one for recovery without giving any info to hackers (assuming you trust the email provider). Definitely less secure than only a public key being exposed, but maybe an acceptable tradeoff for the convenience of an existing established solution?

You rule out social networks, but why? Wouldn’t a fediverse microblogging (or full blogging) platform work fine for the purpose? Just pick an irrelevant username and a strong+unique password and only access your account through tor using any and all relevant best practices.
Given you want the continuity of the author preserved, I don’t see the functional difference between the posts being associated with an anonymous account and them all having your public key. Am I missing something?

Your build looks good (setting the ongoing intel issues that somebody else already mentioned aside), but personally I’d consider a different drive than the Samsung - it’s a great drive, but usually overpriced imo. If you can get it for a good price then absolutely go for it, but most times I find sn850x drives significantly cheaper and insignificantly slower. Otherwise, the only other note I’d make is that grub is abysmally slow at higher resolutions on chips with no igpu, at least when using a nvidia gpu. I’m not certain if this would apply to an AMD gpu, and either way you can just use something better (cough cough refind) to avoid the problem, but for anyone who just wants the default out-of-the-box bootloader on most distros to just work properly it might be worth spending the extra ~$40 for the K series instead of the KF to get the igpu. It’s not something I’d recommend doing personally, but it’s at least worthwhile to know about when you’re making the K/KF choice imo. Anyway, good luck with your build and have fun with setting everything up!

In Canada we have Kijiji, which is… not perfect for privacy, but at least it’s not facebook