Cassa, you have described nothing which gives the UK any leverage in negotiations whatsoever. What do we actually have to negotiate with?
You're right, the EU is going to lose a large contributor. This is a foregone conclusion, it's an integral part of us leaving. Not even the softest of soft Brexits has us regularly contributing to the EU's budget in future. We therefore cannot use it as leverage because those contributions are going at any rate.
What else have we got? The fact that 3m EU citizens are here? Well, they're leaving in increasing numbers because they feel uncertain and (more importantly) unwelcome. Intelligence sharing? This would be cutting off our nose to spite our face. Trade? We do indeed run a trade deficit with the EU, but that bloc still represents some 44% or more of our exports while we represent about 5% of theirs (Brexiteers often quote the raw numbers here without referencing the proportion they are of each party's exports). Even within the Eurozone I believe the highest exporter to Britain is Germany at about 15%.
Even if every nasty thing you've ever read about the EU is true (and I severely doubt it is), even if leaving is good for us in the long-term, the way we have chosen to go about it has put us in an extremely weak negotiating position. It's 26 countries v 1. We have no leverage and appear to have no strategy. The government, furthermore, keeps insisting that we always have the option of WTO trading terms (or "no deal") and yet seem to be in persistent denial about how undesirable that option is.
I'm not "anti-British", cassa. I like the UK, and I'm quite happy to be from it. I like living here, I mostly like the people, I like the culture and the history, and I like the weather. But no amount of patriotism or preening about how lovely Britain is can change my opinion - we've put ourselves in a crap position.