I’m expecting the enquiry, when it eventually comes out, to find that delaying lockdown contributed to the spread of Covid and therefore excess deaths.
That is just one factor.
Others include the way the elderly in care homes were exposed, delaying of mask-wearing, Eat Out to Help Out, and so on.
I don't think there's much doubt that it is Covid which has either directly or indirectly caused excess deaths. I get quite cross when it is implied, as the headline in the op does, that lockdowns caused the excess deaths.
Lockdowns didn't cause deaths. It's perhaps debatable whether they were the most efficient way of preventing, or at least slowing down, transmission, but it is Covid itself which has caused the excess deaths. Lockdowns were a last ditch attempt to slow transmission because it was obvious that people wouldn't voluntarily self-isolate or keep away from others. Most transmission happened between people who knew those infected, so whole households needed to be isolated. There wasn't enough support for people to do that and there was a handful who refused to comply.
Covid cannot be equated with flu. It is not primarily a virus causing respiratory disease. It causes blood clots which block oxygen to all the major organs of the body.
I am cynical about whether the enquiry will tell the complete picture.