1. “sort”: that’s the word for the options of “new”, “scaled”, “active” etc, right?

Yep https://join-lemmy.org/docs/users/03-votes-and-ranking.html

3. @Die4Ever pointed out there’s a “Show Read Posts” option in the settings. I’ve unticked that and will see how it goes.

I honestly don’t use this feature myself lol but I hope it helps you!

In your settings on the website there’s a checkbox for “Show read posts”, uncheck that. Some apps have the same feature or similar. Some apps also have an option to mark as read when you scroll past a post without opening it.

it depends if your Lemmy instance is configured to copy and host images, or proxy images (in which case they won’t get your IP but they’ll know when you look), or neither (they get your IP if they’re running their own instance or self-hosting the image itself)

I just sent myself a PM to test:

programming.dev shows the image as hosted from retrolemmy.com

it might also be currently bugged: https://github.com/LemmyNet/lemmy/issues/5538

It also reduces the possibility of being tracked