The best way to reset UK-Germany relations would be a change of government in London

As a new paper by Luigi Scazzieri of the Centre for European Reform notes, Germany and the UK signed a “Joint Vision Statement” on security in 2018; they are both part of the “Northern Group” of states around the North and Baltic seas; along with France they comprise the “E3” states crucial to the Iran nuclear deal; German leaders among others have in the past contemplated the idea of a European Security Council that binds in the UK. 

Yet as Scazzieri goes on to argue, the limits of such initiatives are set by German concerns about anything that smacks of the UK trying to undermine the EU: “Germany is attuned to smaller member states’ concerns of being excluded and Berlin stresses it does not want to undermine EU foreign policy and wants to involve the EEAS [European External Action Service, the EU's proto foreign ministry].”