Well we actually have a very good idea of how many people would die of Covid if the entire population of the UK got Covid.
We don't know how many people have ... whatever you are proposing we compare that against.
So faced with the options of "prevent the deaths of over a million people" and "matz1 doesn't like lockdown but doesn't want to talk about or quantify it" I think the choice is pretty clear. Unless you want to elaborate further?