There are definitely some drawbacks to Apple here, it is challenging to properly isolate things on macOS/iOS, especially compared to using Qubes or user profiles on Android.
Compared to Windows the difference in privacy is a complete no-brainer though. The word of warning I’d say is that Apple is heading in a pretty poor direction as of late, and I’m not super optimistic about what the state of their ‘ecosystem’ will be in the next 5-10 years. But for now compared to the commercial competition they are still far ahead of the pack.
As far as Linux, the security downsides are vastly overstated by many, and it provides a more than reasonable amount of protection for most people. For someone juggling multiple identities like yourself I would still lean towards Qubes.
You did not specify who you think you might be targeted by, and you don’t think you are a target now, so it seems likely to me that Linux would be perfectly fine for you. There are not really accounts of people on Linux being compromised outside of targeted law enforcement investigations. A well resourced state actor is a completely different situation than a stalker or criminal targeting you, so keep that in mind.