Imho the UK post Brexit lacks political leadership that knows how to manoeuvre the competing political factions within the Conservative party and balance the short-term and long-term economic pressures it faces.

Trump was the UK's best chance at a US trade deal and the terms were too unpalatable for the Conservatives. This imho was a self inflicted economic injury. Demographically most of the West (including the EU) is in terminal demographic decline and in particular the European flavour of socialism (i.e. a deep belief that the State is a necessary part of economic development) will start to fail under the crushing weight of an ever larger aging population.

The US and Mexico will be the most important growth export market for the UK going forward into the next several decades, and the cost of a trade deal with the US will increase the longer the UK gets desperate.

Alternatively the UK could try to create a Commonwealth free trade zone (and include the 2nd most important market India) but that takes imagination and leadership that again I think is lacking.