Reminds me of a CS professor telling me that a COBOL programmer will never go hungry ... and it's still true :-)
MS stack will be high quality and used by clients with $$$ for the rest of your career.
With that said, any serious non-MS shop will be happy to have your experience and so switching up stacks shouldn't be a problem either if you find a good team.
I imagine in two or three hundred years though we will have moved past COBOL completely. That being said the idea of some future advanced civilization trying to wake up some old programmer from cryo sleep so they can decipher an ancient mainframe that is still somehow running does make me laugh!
Azure is not bad compared to the options. Also, MSFT is throwing a lot of brain power at it (notable systems researchers from MSR). Curious what you consider is better?
most of my bad experience with Azure is the control interface, which is worse than AWS/GCP in every way
random incomprehensible error messages, near constant UI timeouts and terrible UI performance and experience (artifact deployment has been "skipped"? why? no way to know), etc
the Windows VMs are also extremely slow compared to my employer's non-azure VM, with the Azure VMs having double the VCPUs, disk IOPS and RAM (despite having the same "stack" deployed on it)
One thing Microsoft does that Google does not is persistently push their garbage until it's actually not bad.
Blazr is relatively new compared to Microsoft's other libs but I'm sure in 5-10 years, it will be solid. It took .net core years before it became decent.
MS stack will be high quality and used by clients with $$$ for the rest of your career.
With that said, any serious non-MS shop will be happy to have your experience and so switching up stacks shouldn't be a problem either if you find a good team.
I would just apply broadly and go from there.