Exchange rates are relative. The US still has significant inflation, which is a result of (among other things) years of loose monetary policy. And the EU and UK

Exchange rates are relative. The US still has significant inflation, which is a result of (among other things) years of loose monetary policy. And the EU and UK central banks have also been printing for years. The US is quicker to hike interest rates (effectively, reversing the money-printing process) which is one reason why the dollar is strengthening against the other currencies.