If your customers are known to be antagonistic to business partners, the correct answer is to diversify them as much as you can, even at reasonable costs from anything else.
Yep, you can be close allies with a nation and have many shared interests, and even a trade deficit with them as we in Britain did, and then they stab you in the back with tariffs.
That's also a lie, it's only antagonistic when one of the sides is controlled by a psychopathic asshole, and it being antagonistic is a serious drag for the gains of both sides.
That means deprioritizing your largest customer.