Well, no shit we're bound by their rules. Let's not pretend it's some kind of revelation where I'm gonna smack my forehead and say 'zomg I had no idea!'

Well ok. So we agree there's rules. So my sovereignty and democracy argument is another way of saying "I don't want to play by their rules because they are not subject to the will of the British people". It's tenuous as fuck to say they are subject to the will of the European people, but their sham of a democracy at least tries to pretend that much. It's a sham because there's no alternative (other than to leave outright of course). It's a one-party system.

Explain to me how following rules costs us our sovereignty or democratic control.

The ability to opt out without a shitshow, referendum, then more shitshow. We can abandon a trade agreement with the stroke of a pen, and instantly deal on WTO terms. Leaving the EU is a lot, lot messier, and not something that can also be undone with the stroke of a pen.

Membership of the EU and a bilateral trade agreement are very, very different things. A trade deal is not a challenge to sovereignty. You can say "fuck you" at a moment's notice if the rules are unacceptable. We did not have that power as an EU member, we still can't actually have trade deals with other countries until 1st Jan. A trade agreement between us and USA, for example, does not mean we can't then have a nice deal with NZ. We retain sovereignty. We are in control of our economy.

This really shouldn't need to be said. The difference between a trade deal, and membership of a political and economic union, in terms of sovereignty, is monumental. I can only assume you don't know what "sovereign" means. To you, it seems to mean "doing what you want". That's not what sovereign means. It means "absolute authority". It means no other country is an authority to the UK. You can argue maybe USA are an authority, but geopolitics is another matter.

Is that your answer to how we're losing out on sovereignty and democracy?
You're just refusing to hear me.