Your link is talking about "confirmed cases". Belgium is high in that list because they do a lot of testing inside and outside hospital, and so many of the peop

Your link is talking about "confirmed cases". Belgium is high in that list because they do a lot of testing inside and outside hospital, and so many of the people who die of covid-19 have had a test to confirm that, and because Belgium is including deaths that happen outside hospital. The UK however has only just started testing people outside hospital, and has only just started including deaths outside hospital in its figures. (And even then, not all cases confirmed by tests are included. We have a complex system of "pillars" and only some of those are included). Yet, despite not including all deaths, we're still 4th in the table.