WRT furlough, I think the point to take is that state support is a practical necessity if governments want to prevent millions of people from working whilst also keeping them at home and behaving. And that in March 2020, because lockdown wasn't in the disaster planning, we had no existing designs or systems and it all had to be thrown together over a few days, with no extra resources for anything like means testing. So it could never have been anything other than broad brush.
Obviously this is less the case for later lockdowns because there'd been more time then, but in March 2020, as soon as the government decided on lockdown, that meant a cobbled together furlough system was an inevitability.
Although even later on, there's the issue of what impact it would've had on compliance if the resources had somehow been found to means test furlough. Also think how many took furlough for childcare, which actually was a pretty essential plank of lockdown in that it got contacts down. If all those who'd still been able to had all worked instead, many of their children would've been looked after elsewhere and caused either further pressure on the available school and childcare provision or been looked after unofficially by whoever was available.
This isn't a pro furlough argument btw, or even a pro lockdown argument, only saying that there wasn't a lockdown option that didn't involve very broad brush state support. Means testing it wasn't practical. If you're going to prevent people from earning a living and/or boot their kids out of school, enough of them need to be paid enough to comply otherwise you might as well not bother.