you’re supposed to use your personal account to create a business “profile” for the company you work for. the company is supposed to have created a space for it on business.facebook.com

creating a “pro” facebook account is indeed disallowed by the facebook’s policy

I’ve done that multiple times. works well but you indeed to not have a clear separation between work and personal life, which is not good. I don’t mind it because I don’t use facebook, but it could be a problem for other people.

I honestly don‘t get how facebook think the world works…

Usually through enterprise social media management apps. Hootsuite is the first that comes to mind, I'm sure there are many more. But I don't know what the auth looks like underneath that, an API for sure, but whose token?