I know half-a-dozen people who died from covid over the span of 2 years and it's probably a bias of some sort because I'm pushing 50 and so my aunts/uncles/older in-laws/friends' parents are all in their 70s-90s so I knew a shitload of senior citizens/elderly.
But on the isolation thing, help me out here, I'm not trying to be a dick or insensitive, but when you say "isolation" what are you talking about? We were never stuck in our homes like the Chinese were and I'm always curious when I hear people talk about "isolation".
In my case, my family, weather permitting, were out walking or biking every single day, walking around parks or just down the creek, we were driving out to pick up food at various restaurants and grocery stores (whose employees were obviously coming in), we were getting stuff delivered from Amazon, Walmart, etc. I was on Zoom 2-3 hours or more a day, my kids were on Zoom 2-3 hours a day with classmates. We had multiple evenings during the week where we were on Zoom with my wife's Sunday school group playing games or just shooting the shit. I had 3 different zoom calls setup every week with various parts of our family where we'd have anywhere from 5-10 family members on a call, plus I had a regular zoom call going with about 20 high school friends (and prior to that our interaction was the occasional text or facebook message or like). In fact, I spoke with some family and friends far, far more during COVID than I did before or after. I mean I had a calendar on the wall listing all of different things we had going on every single day or night in terms of zoom or phone calls or online gaming with friends (Roll20.net was amazing).
So when I hear people talk about "isolation" during COVID, I'm always curious, because I was arguably more connected with family/friends and some people I did some freelance projects with during COVID than I ever have been before or after. In fact, our older relatives that we rarely talked to, we were talking to every week or two for an hour or more, and checking in on them, etc. Now it drove me crazy that my kids and wife were home all the time, but that was just a lot more family time than anticipated.
I will say it did affect kids in school at certain ages - that needs to be studied, although many have seemed to have bounced back or even forgotten about it (depends on the age of the kids).
What I'm getting at, is what kind of "isolation" did those people go through, that died? I freely admit that I've joked about how all of the preppers who had their bunkers or survival closets stocked full of Jim Bakker 'Bucket of Mashed Potatoes that will feed a family of five for a year' were melting down that they couldn't go to SuperCuts or eat in at Chili's, but what did isolation look like for the people you are talking about? Because I always felt like we were never fully isolated - we could still get out and walk or drive around, or put on our masks and go stand 6 feet apart in HEB.