It is trivial to have multiple accounts active on any Android phone, and install apps using any of them. (And once installed, the app is not tied to the specific account in any way.)

Settings > Accounts > Add account > Google. And to choose which account to use for Play, just click on the profile picture in the app and choose the account you want from the drop-down menu.

The accounts can be tied to different countries. So there is no need to have multiple phones.