The SIM Swap would seem to be a bit more accessible to the average fraudster. Hacking SS7 apparently requires setting up a "hub" and obtaining a carrier license from a lax country. That is, until we get to the bit about "illicit merchants offering ‘Connection-as-a-Service’ to such hubs."
Carrier license sounds much more involved than what it is. It's not uncommon to sell full SS7 access to companies that are not operators in the regular sense.
https://www.kaspersky.com/blog/hacking-cellular-networks/106...