I don’t know how you would force compliance with a different instance though, especially if it is not located in the EU.

If you're in the US and they're in the US or countries that have copyright treaties you can request removal under DMCA since you own your posts and comment content. And if you don't agree to their TOS or licensing it's a kind of a grey area for them. Still not completely foolproof since if Instance admins are willing to go further than you're willing to go (i.e. not complying without a lawsuit), you can't really do much about it.

In the end we can only control ourselves - e.g. note I'm writing this from a PieFed account:-). But yes Sublinks is a very exciting development as well, though I have not heard any developments for many months when it was mentioned that it was not stable yet.

Yeah especially because Rust is much harder to contribute to. Once Sublinks gets off the ground I feel like there will be more people eager and willing to contribute code. I'm hoping that it's still going since there would be great benefit in this project being an option.

And yes someone could fork the Lemmy codebase. Many instances including Lemmy.cafe and Tesseract on dubvee.org have done exactly that, though unlike Mbin (since Kbin is now defunct) they don’t want to get too far ahead of the main branch so that they can still receive future updates easier, whereas PieFed and Sublinks and Mbin are each entirely separate projects from Lemmy to begin with, though they are interoperable with those federated communities which is awesome 😎.

I believe Programming.dev does it too, they call it Pangora though they're currently restructuring it to be a fork of Sublinks so they haven't worked on it much at the moment. Also Tesseract is an alternate frontend of the Lemmy software, not a different software. It does improve Lemmy greatly though.