Neither work profiles nor this will protect you if your device is subpoenaed. That’s why I have two separate physical devices (well, 4 if you include laptops). You should never mix work and personal devices.
Fine, if they are company provided. But I will not buy a phone (and SIM card) myself for work usage. When I possibly can I make calls with the work landline phone, but it's not always possible (or I have to have customers send me messages on WhatsApp etc) so I use my personal phone.
Not something I like since there are customer that calls you even outside office hours (but I just block that calls).