I'll be honest with you, the British Empire was in many ways no better for my ancestors than it was for yours. The governments of the time were, like the US government now, largely dominated by commercial interests. The business people looked to the British goverment to protect their overseas assets and stabilise the political situation in the countries concerned. That required a lot of men and equipment that could only be found or made here.
Your forebears were probably made to work as labourers in tea and cotton plantations. Mine were either soldiers or Yorkshire coal-miners. I very much doubt that the standard of living of the one was very much different from that of the other. But what they did have in common was that a very few people were getting obscenely rich off their hard work, low wages and grim living conditions.
There has always been a strand of Bristish Conservatism that admires America and the American way of doing things. But, unlike Churchill and Thatcher (spit when you say those names), Boris Johnson is no 51st-Stater, but a Little Englander. Also, the whole Covid-19 thing has rammed home to everyone just how much of an asset the NHS is and how badly it's been neglected over recent years. In fact, the current government is planning a raft of legislation to roll back the pre-privatisation measures that Cameron put into place.
The monarchy is purely ceremonial. The Queen is merely the living representative of the Crown, because an institution can't physically sign Acts of Parliament. The Crown itself is apolitical, as are its subsidiaries in the judiciary, the military and the Civil Service. Politics happens in Parliament, which is authorised by the Crown to enact the will of the people. The bicameral structure is meant to acknowledge the idea that the Commons and the Peers of the Realm have differing views, but the fact that both needed to agree on any Bill meant that a balance was maintained. Now, of course, the House of Lords can only suggest amendments to legislation, and the House of Commons can override them.
Brexit is proving less disruptive than many feared. It's in the interest of both Britain and Europe to keep things going, trade-wise, as smoothly as possible. The spectre of food shortages and so forth appears to have only slightly more substance than that of the dreaded 'Y2K Bug" of 20 years ago! Politics may prove more problematic, as the French and Germans compete for European hegemony without the UK to referee!
As someone who si familar with "Warhammer 40K" culture, the term God-Emperor implies a living corpse in a life-suppport system, served by fanatical legions of genetically-engineered super-soldiers. Trump wouldn't go for that - not if it kept him off the golf course!
As for his 74 million supporters, they all seem to be of singularly low intelligence. As such, a years' silence from their idol will be enough to make them forget about him. Especially if they can be provided with distractions such as affordable medical care and a living wage. Just keep him off Twitter and steamroll the legislation through Congress.