England is a country. The UK is a country.
People in the UK would refer to England as a country and most people would actually be confused if you referred to the UK as a country, even though it technically is. People in England don’t really think of the UK as anything other than “the UK”. People from Scotland, Wales, and Ireland have more nuanced takes.
I'm English and I don't think England or Scotland or Wales are countries. People get confused because of football and rugby. They're nations. The country is the United Kingdom.
No one is confused if you can the UK a country, or if you call England, Wales, or Scotland a country.
You might get a tedious person saying something like "actually, Wales is a principality".