

It’s not so much about nuclear envelope and more about ends. DNA polymerase (an enzyme that builds new DNA) cannot copy the whole end - there are a few bases that should be at the end but cannot be added. Eukaryota deal with it by a complex mechanism (they have telomeres), but it allows for multiple chromosomes and therefore larger genomes. Bacteria have a circular genome instead, a circle doesn’t have an end, so they can copy as much as they need.
BTW, mitochondria and plastids, being former bacteria, also have circular genomes.
Yes. But if you have many complaints from MANY MANY users, it may not mean anything serious, it could still mean a very small fraction have problems. Absolute number means very little without context. That’s the purpose of the previous comment. Please note how it doesn’t say anything about qualities of Windows.