Bullshit. I can use docker without the docker hub very easily. Anyone can host docker images, and docker allows this, no weird hacks needed.

Docker does not lock you in with the docker hub though. So no hostage taking.

It can hide cookie banners for you with the right settings. Since gdpr dictates no choice = no cookies, this should block all tracking stuff.

I don’t remember what exactly you need to enable, but you can use DDG to find out.

No (or very limited) editing in Okular…

Miracast is basically just wireless HDMI

Yes

Don’t underestimate a pi! If you have a 3 or up, it can easily handle a few more things.