You have to take into account what evading immunity can mean. It means it can infect people and they can spread it, it however doesn't mean they have a serious disease or need hospitalisation.

The issue with COVID-19 was lack of any immunity at all, while early variants infected the lungs, later, more infectious variants started to infect the upper airway more seriously, but the reality is while this allows more effective spread, the upper airway is largely irrelevant, it isn't what absorbs your Oxygen supply, it is just causes a really bad cough instead.

Then you have to take into account this issue isn't a disease existing, it is everyone getting it at the same time, and then a significant percentage needing hospitalisation at the same time. Imagine everyone broken their arm at the same time, A+E would collapse, orthopaedics would collapse, any requirement for surgery would be overwhelmed (it is needed in 2 weeks), there would be no ability to get people effective rehabilitation, and people would start dying from complications of broken arms.

That is essentially what happened in COVID, with "a broken arm" being an unknown disease with an unknown treatment pathway, which once again is a massive problem. It is fine if you can treat 95% of your patients with X known treatment, it is another thing when you are trying to work out what treatment is needed, then when you do, don't have the equipment to implement it, or the specialists to manage it.

Nope.

You have one years data set.

For all you know that have 1000% more natural gas than any other year.