UWP is the future of Windows - correct.
I'm not sure any significant part of UWP has ever been in the kernel per se.
It sounds like you're a consultant where taking risks on behalf of your customers, no matter how small or logical the risk, is obviously not part of your job description.
Your offerings of good luck appear to be disingenuous.
I suspect you'll say "7 years is nothing" and maybe it is nothing. But it is still something. It is long enough that we made a couple bad framework/library dependency choices early on and to have learnt lessons from such mistakes.
By far the biggest technical challenge we've faced in that time is the .NET 5 migration - but even that might turn out to be a lot easier than I currently envisage.
Still no VS or Blend tooling support, no project templates and .NET Native requires workarounds with stuff that most corporate enterprise developers don't care to learn.
So if their IT goes down and the reason is that a risky loving consultant used unofficial workarounds, I rather not get unnecessary phone calls.
As for the wishing luck, I was being honest, take it as you wish.