> Instead of a residential IP service, I used an (undisclosed) different, impeccable approach, which won't work for all use cases, but did for ours

3G/LTE because all mobile providers use CG-NAT?

(I also discovered that my old DSL ISP accepted its dialup provider's credentials for PPPoE). Best part about PPPoE is that you can run multiple sessions over the same line/modem.