Yep, similar experience with 12 spam calls today (so far) within last couple of hours to my Sonic Fusion number, from the same NPA/NXX with random last 4 digits, all about Apple iCloud account. This is pretty much denial of service attack on my landline, and Sonic should be vigilant, since this behaviour is not too hard to trace.
I understand they're working on STIR/SHAKEN support; in the interim, marking repeated calls (say over 5) from same NPA-NXX, with different 4 digits, as voicemail spam, would be an option i'd love to be able to enable. Obviously, this allows bad guys to send incoming calls from my neighbours to a voicemail spam folder, but this would provide choice. It does require implementing voicemail spam functionality (i.e. do not ring, send directly to voicemail do not notify (or use alternative email to notify)).