Not really. He could be force suspending Instagram apps and rotating IPS before opening the app. I've even spammed with one account in my personal phone and getting blocked that specific account, but not my other 3 personal accounts. The same applies for twitter.
Personally, I think this is the way to proceed nowadays
Still, I'm trying to discover how to do the same, but for Google/GMB. Currently, I can only stand up to 1/acc/phone. I know for sure that it is possible to do more with less.
Anyway, I find this solution super expensive. It's way better to simply make proxies with 4G modems and simply use the infinite IP pool, while still using the phones.
Also, the phone management, it's also a big hindrance. Imagine having to manage 750 IG accounts with 150 phones all over the place. Maybe in a 3rd world country, you could hire a couple of people for peanuts to manage a portion of those phones. But making automation systems, with this router/phones setup, feels a nightmare.