Problem with a dual sim phone is that all it does is give you two phone numbers and two different network connections.
It doesn't separate out different mailboxes / histories / address books, everything gets lumped in together - you don't get discrete separate identities.
Better off with two phones
I agree better off with two phones but with some Android you can separate users. If it supports E-SIMS you can usually have 6 numbers. You can have Email, pictures, notes and app that are totally separate on reboot it goes to the default user.
Latest Google Android you can have a separate sandboxed area a bit like the Samsung Knox security layer.
I have this on my punting phone. Default profile looks like basic apps Waze, X, Gmail etc, 2nd user (punting user) has Google Keep with my punting info, G-Maps , WhatsApp etc
I have little security features that wrong pin to unlock 3 times takes a photo and location of phone and sends it to me in the cloud where I can consider remote wiping or making the phone sound a loud alarm "This phone has been stolen, please call the police" until turned off / reset.
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