Just because someone else has a broken leg it doesn’t make your sprained ankle hurt any less!
So just because some people have it worse doesn’t mean you can’t find things hard (or harder than normal - it’s all relative)
By some of your reasoning none of us should be complaining at all as there’s plenty of people in worse off situations - 5 years olds working in factories, while families Africa affected by loss due to aids, people in war torn Syria etc etc bet most of them would look at us and think we all live pretty privileged and golden lives!
Yes - Kate Middleton has a massive house (and a choice of houses to spend lockdown in), most probably a nanny/housekeeper etc staying with them, private education who are probably providing a lot more support than some state schools are able to due to budget etc, private healthcare so no worries when they catch covid that they won’t get the best care/ventilator etc, Jobs are secure and if not they have mega bucks in property/trust funds/investments etc
But they have 3 kids and I’m sure they are doing some of the care and homeschooling, they are still not able to see family and friends like the rest of us, bored and fed up like the rest of us, not able to sneakily break any rule (which most normal people probably have done eg gone for a walk with a friend when strictly not supposed to etc) etc
I’m finding lockdown very hard mentally, it is hard but I know that DH job is fairly secure, I’ve still got a job (although hours cut by 1/3 after furlough ended), we’ve managed to buy a house, none of us have got covid (or if we did it was very mild), kids state schools have provided a good online provision etc etc. I know there are plenty of people who have it worse than me, lost jobs, loved one shave died, kids have greater special needs than mine do, have lost their houses as can’t afford the mortgage, have health issues etc. I’m still entitled to have a little moan.