Questions about Samsung 990 Pro

I recently bought and installed this SSD. Now I have read the reports about the rapidly decreasing life span. Is the 1TB model also affected? I don't want to keep it if I have to replace it in a year. Do you already know more? Thank you.

This is supposed to be one of the fastest m.2 SSDs, but for me the boot process still takes about as long as with a 2.5" SSD (with Windows 7, approx. 15 seconds). A cheaper one would probably have sufficed...) ?

Could any recent buyer give me any information about the health and life span issue for this ssd? Is it still happening?

Work with IMac 4K retina 21.5 inch 2017 without adaptor?