Phantom multi-chain beta uses the same dapp connect option as MetaMask. If you use Phantom and MetaMask side by side on the same browser and profile, you can select which one you want to use by Default with these steps:
Alternatively, you could also:
Move Phantom to a Different Browser
Go to Phantom settings > security & privacy > show recovery phrase
Backup your recovery phrase
Install Phantom extension on a different browser such as MS Edge, Brave, or Firefox
Select "I already have a wallet" and import your Phantom secret recovery phrase
Move Phantom to a new Chrome Profile
Go to Phantom settings > security & privacy > show recovery phrase
Backup your recovery phrase
Add a Chrome profile:
Install Phantom extension on the new chrome profile
Select "I already have a wallet" and import your Phantom secret recovery phrase