ok, let's clarify some wording / nomenclature first:
[1]
Germany, France, Spain, etc.. will not pay tariffs on goods sold to the UK.. the UK will have to pay such tariffs, making the product more expensive, IN the UK.
EU countries would pay tariffs on UK products they buy, if the UK imposes such tariffs..
And as you said, the UK does not seem to have a lot to sell, but a lot to buy.. so this is an issue for the UK (which is why they want "a deal", and one that protects them the same as before, while they don't want to be a part of 'it" anymore.. this is where the whole mess starts).
The UK has profited from a free trade agreement with 27 EU members, being allowed to imprt tariff free much more than what they export.. a big deal, an advantage for the UK.
United Kingdom - trade balance of goods 2007-2017 | Statistic
[2]
Now, one thing i'd like to hear from you.. what is it that you think the UK has to sell, that the EU should buy, but doesn't ? What is the big wealth maker in the UK ? What do yo have to offer, better than the rest of the world, that is on high demand, but the EU just out of spite doesn't want from you ?
[3]
And for what other reason than goodheartedness should the EU keep all their advantages to the UK as they are today, when the UK openly says "we don't want you and your rules anymore".?
How would that be fair to all those other countries who remain in the EU, and pay their share ?
you're living in a dreamland, really...