The following FAQ will help explain about locks and repeaters. It applies to all brands of zwave locks. (The thread title is a clickable link)
That said, that the problem was with your lock sounds like a device issue, not a network issue.
Kwikset is a budget brand. On a scale of good/better/best they are probably right in the middle of “good” where Schlage and Yale are at the high end of “better.” That doesn’t mean switching brands will fix all your problems overnight, there could still be network issues or cloud issues, but it does mean that other brands make better locks. But then they cost more, too. So it’s a personal decision.