.016.A1 is global.
.016.A4 is EMEA (Europe, Middle Eastern, Africa)
.016.A5 is Australian carriers
.017 is US carriers
It makes no difference whether your device is unlocked or not; the only thing that -might- make a difference is the model number; there was a difference on the Pixel 5 between US and ROW phones. From a software perspective you probably won't see any difference. What changes between the versions is the radio/baseband version which may contain improvements for certain regions. Use the version for your region.
Any phone running on the Verizon network, despite where you got your phone, is normal that you don't get the OTA very fast. I've also heard a rumor that Google stopped pushing the December update, but all I'm doing is further spreading the rumor as I haven't come across any news articles about it.
If you read the last 2-3 pages of that thread, you'll see a bunch of others have rooted using a different (not even Canary) version of Magisk. They're more recent, they just haven't made it to the Canary channel yet.