@yaphets77 , some snake oil seller has somehow convinced you that a rooted Android is necessary to create Google Ads accounts and wants to (as YOU have mentioned) sell you a rooted Android. Rooted Android is no big deal. Anyone can easily root an Android device. If you are so determined, then just buy a used Android phone (easily under US$50) and root it yourself, instead of buying it from a snake oil seller : you may end up saving perhaps hundreds of (US) dollars.
what you wrote is nonsense. try to make a multi-phone from a regular android phone, it will not work. no need to write something why you don't know. Do you use rooted Android? I think no. But I have colleague who use it.
Firstly, not every phone can be made a multiphone, only certain brands and models,
secondly, this must be done correctly (create root and change imei, MAC address and system info),
thirdly, no one gives you a guarantee that Google will treat you well, but the fact that you will differ from all users of the antidetect browser is a fact (perhaps it will help),
fourthly, you still need to use high-quality proxies, and they should be defined as a Linux device (there are most Linux on the market, but there are also Windows, Windows is needed if you work with a browser antidetect).
For the author of the topic: you should not buy anything from the first person you meet, look for other reliable suppliers, but you can try work in google with a rooted android!