First: Good for you, enjoy the journey! Second: Just as others already pointed out, Mastodon is not really a beginner project. You want to understand what you are doing, not just make everything work no matter what. Some reasons why I’d not start with Mastodon:

• Complex deployment stack (for beginners)
• Needs regular maintenance
• Security considerations (if you haven’t managed/hardened a server before)
• Long term project

So instead: Have a look at awesome-selfhosted for ideas. A personal dashboard, photo gallery or a PiHole/AdGuard is a good start.

About Docker; it’s a bit more than just dependency separation. It’s a kind of virtualization, but without each container running it’s own kernel. Advantage is: Docker images run (with some configuration) relatively lightweight out of the box. So there’s no need to install the applications natively. While I’m a great fan of Docker, you’d probably learn more installing things natively in the beginning. Or maybe do both, it’s up to you. However, if you decide to use Docker, be sure to understand what’s going on under the hood. That’s where the fun begins. Everyone can pull and start images, but not everyone knows how to customize or build them themselves.

No matter what you decide to do, have fun. And if you’ve any questions, there’s plenty of documentation online or just ask. The selfhosting community is very welcoming towards new members ;)

I get your point. Then, why not start your own instance with rules that you approve? I know, easier said than done, but that’s the nice thing about the Fediverse. Next to the general purpose instances, there are many “themed” ones with focus groups such as musicians, journalists and so on.

You lying to yourself or have unfounded expectations.

Nobody mentioned any expectations hm…

Everything on Mastodon is in plain text, there is no encryption, and servers get mirrored.

That’s 100% correct, and I think it’s important to explain that to non-techy users.

It’s only the login info that stays with the instance […]

Technically yes, but I’d cut the “only” because login info includes the users email. So in case of a raid or data breach, I’d like to know about it.

The entire point of why Mastodon was ever started was censor evertbody that has the wrong opinion. Twitter wouldn’t delete people because of what they believe, so Mastodon was developed to ban IP address so only approved speech could exist on the internet as far as they are concerned and can avoid ackniwledging the real world. A high number of people on there, especially the admins, live in cult

I don’t know what places on Mastodon you’ve visited, but that’s not the point of Mastodon or the Fediverse in general at all. But we don’t have to start a discussion about that since you seem to already have made up your mind about it.

As far as I know they seize everything if there’s a warrant. No matter whether it’s relevant for said warrant.

Edit: Sorry, misunderstood your comment; Don’t know what the reason for the warrant was.