What, social lives? Get outta here with that nonsense and be a hobbit like the rest of us :)
Seriously though, if you're thinking on a phone I'd reccomend just creating a second profile instead of getting a whole new device. The apps won't be running when the profile is running, and as a bonus you can usually restrict the profile's permissions. Also consider checking out web wrappers (e.g. frost) or PWAs.
On a desktop you can always just use the web version, bonus points if you auto clear cookies or have a separate profile.
Edit: if you already have a spare then that might work better than profiles.
Yes. Brave focuses on providing random data points each time it's asked (e.g. screen size). A hardened Firefox will try to provide a generic fingerprint.
Apples to oranges more or less, I'm unaware of any proof that one or the other is considerably better across the board. Though my gut does tell me that randomization is a lot better in the specific situation of regularly signing in and out of accounts.