FYI, I've rarely seen any Apple NVMe SSD to be at 100%. Most of them which I've checked are 99%.
Also, sometimes the manufacturer's don't always implement SMART reporting correctly. In fact, many times the manufacturer may implement these items backwards.
Usually any small changes should be ignored except for the values associated with "Media & Data Integrity Errors" which I find will usually show up where the user will actually encounter system related issues. These "Media & Data Integrity Errors" is the SMART attribute to be most concerned about. And possibly any "Error Information & Log Entries".
Like I said before, most SSDs will write PBs of data before wearing out so the "Available Spare" value should not really be much of a concern. I've rarely seen this value lower than 99% (unless the values were implemented in reverse of course where it would indicate "used" instead). Plus many of these NVMe SSDs (especially Apple's) don't show enough health information to really understand the true health of the SSD. Since you are paying close attention to this information, then just observe & learn how Apple's SSDs and the SMART information changes over time. This will tell you exactly how Apple has implemented these features.
Most SSDs will fail suddenly with absolutely no warning due to the SSD's controller failing. There is no health monitoring of the SSD's controller. Otherwise the "Media & Data Integrity Errors" and the "Error Information & Log Entries" are going to be the attributes of most concern for you at least from my own more limited observations of the Apple USB-C Macs' internal SSDs. You will drive yourself crazy otherwise. I've been using SMART to monitor HDs & SSDs for over 20 years to support my organization's computers (SSDs since around 2010/2012+).
