DigitalOcean's guides in general are pretty good for all sorts of things, whether it's a generic discussion of a concept like the ones you've posted, or a step-by-step guide for installing and configuring specific systems or software. Even if you're not using DO as a host, much of what they suggest is still very useful.
losttourist
Do you want zombie orphans? Cos that's how you get zombie orphans. Listen to the AI, it's trying to save the world from becoming a dystopian TV series!
The internet that we invented was a good internet. It's only later on it became a place for misinformation and adverts.
That looks amazing. In the last year or two I've found a pretty good, reliable dough recipe, but I'm never really satisfied with the tomato sauce I use. Do you have a recipe you stick to?
markdown support
If you are on (or migrate to) a server using the Glitch-Social fork of Mastodon, you'll get markdown support. It's a game-changer, in my opinion. (glitch-soc has lots of other nice features too, btw).
While true, I think most people's concern is that their laptop is stolen and along with it all the access details for their email, online banking and so on.
If you're doing things that mean you're going to be the target of people with the knowledge, time, and technology to freeze the RAM and attempt to recover the data, you're presumably already well aware of those (and other) dangers anyway.
systemd [is] a niche
Maybe in the wider world of all the operating systems installed on all the computers, but for Linux-based computing it is, like it or not, near ubiquitous these days. And in particular for server systems (and this is, after all, /m/selfhosted), good luck finding something that isn't systemd-based unless you're deliberately choosing a BSD or aiming for a system which has ever-decreasing amounts of support available.
what if I'm not using CoreOS?
Podman runs on any distro (or more strictly: any distro that uses systemd). It's essentially a FOSS alternative to Docker.
I haven't run up my own Threadiverse server yet, but I self-host my own one-person Mastodon, also on Hetzner. Yes, it will eat up a lot of disk space, so if you're trying to keep costs down you need to send all the media to S3-compatible storage. I use Backblaze B2 which costs me something like $2/month for 200GB of Mastodon media.
I would assume Lemmy or Kbin would also be greedy for asset storage, as they'll pull in media (images and videos) for any community you follow. So again pushing that all off to a low-cost storage system such as S3 makes a lot of sense.
The developer of kbin, @ernest, has said that automated processing of account deletion requests is on the roadmap but currently it's a manual process.
As you can imagine, for a piece of software that two months ago was in alpha status with fewer than 100 regular users and then suddenly became one of the most-used systems on the Fediverse, there are still a lot of rough edges to be cleaned up.
Yes, I think that 'masquerading' is the key bit to grasp. The MITM Proxy isn't just intercepting the traffic, it alters the traffic as it passes through.