I don’t want to sound like a pedant being at it, but if you asked most people from around the world if the United Kingdom of Great Britain and Northern Ireland is a country, they’d say yes - it has a seat at the UN, it issues passports, it sends and receives ambassadors to other countries, it has set territorial borders and a single head of state.
Doesn’t mean that anyone living in any of the individual nations shouldn’t want independence or feel like the UK as an institution isn’t a bad thing, obviously I wouldn’t argue the UK is a harmonious country, and obviously the worst kinds of people do refer to the UK and individual nations as and when it suits them (the whole is Andy Murray Scottish or British thing).
FWIW I think it’s funny that of the home nations, England is the least country like since it doesn’t have its own parliament / assembly.