The general consensus is that you can safely manage up to five accounts on a single device. However, be cautious about creating them all at once.
For safety reasons, it’s recommended to space out the creation of new accounts by several days, if not weeks. Make sure each account is fully warmed up and actively running before creating the next one.
Ultimately, the fewer accounts you manage per phone, the better. That said, there is no definitive material or guide on this topic, so it’s best to experiment and see what works for you.