Neville Chamberlain is very unfairly treated. He was a great man in the wrong place at the wrong time. In his day Great Britain was considered the most powerful country in the world.
The war changed that.
Eden was not a great man, though his contemporaries thought he was. By invading Egypt and then withdrawing at Eisenhower's behest, he showed the world how weak we had become. After him all British governments have been satellites of the USA.
In the 1970s Britain was regularly called the sick man of Europe and this sense of decline was what led Macmillan and Heath to take us into the EEC - Labour leader Harold Wilson who opposed entry would also have taken us in. The one man who could have prevented it was his predecessor Hugh Gaitskell, who opposed entry but who died suddenly in 1962.
After we joined the sense of decline got much worse during the Labour governments of 1974-79.
Still, even in all those years from Suez to Brexit, even if the British did not know it (and they didn't), Great Britain remained a great country in every way that can be measured.
She has always one of very powerful and respected countries except for two historical periods: during the reign of King Charles II, who was subsidised secretly by Louis XIV, and in the three years when Theresa May was humiliated by Brussels and almost led us to perdition, by becoming vassals of an EU over whose policies we had no influence.
This is what Boris has saved the country from. This is why his trade deal is comparable with the Glorious Revolution (so called, I am a sentimental Jacobite) of 1689.
1689 was the English Revolution and Brexit is the British Revolution.
I give Boris the credit for getting the UK out of the Houdini-like box Michel Barnier and the witless Theresa May had constructed.
I should add that successful revolutions have many authors and the man who deserves most credit for Brexit is the oft maligned Nigel Farage.