I have no problem with a more rational approach to the whole situation. That is, try to get an arrangement in place.
Tariff barriers of course are between any country where we don't have an explicit deal in place. Which at least for now is nearly all of the world! So BMWs may cost a bit more, but so will all other cars from anywhere else.
Problem is we can't get a trade deal anywhere without some legal or political aspects. That's how they work. There are always rules about what can be sold, standards of manufacture, sourcing etc. (e.g. to stop one partner buying cheap crap elsewhere, adding a % and using the trade agreement to sell into the other market).
Oddly, although the agricultural policy may be a monster, UK farmers do quite well out of it. So that lot needs sorting as well.
Our contribution to the EU budget is 13%. Smaller than France or Germany (16 and 19%). Our net contribution is half that of France or Germany, so yes they do like to have our money, but they will probably get over it. I agree that the sudden cut off is not wanted at all.