As I've been trying to compartmentalize my online activities, I've run into a question. Let's say I login to protonmail for my new business email. If I login to discord with a separate digital identity, could someone trace it back to me? I'm assuming I'll have good security practices and I'm just talking through grapheneos.

I have google stuff installed for motifs, and my follow up question is: would uninstalling GSF make it harder to link those two identities together?

It depends on who you mean by someone.
Another discord user will have no idea about your protonmail identity.
Similarly, a protonmail email recipient would have no idea about your discord identity.
Your phone would not reveal private info between the two apps.

There may be a possibility if both apps using push notifications using Google's FCM. I believe it should be anonymous. But Google might be able to glean some connection between the two.

If the someone is law enforcement with subpoena power in the jurisdictions hosting protonmail and discord server, then it's definitely possible. Protonmail will comply with lawful requests for information when activity that is a crime in Switzerland is being investigated. With that, it will be possible to identify IP addresses they have also accessed the discord server.

    Graphite That is very insightful, thank you. So what you're saying is if I access discord or whatever from a VPN along with PM, it won't trace back to me? If yes, how could I minimise this?

      Ratty don't use sandboxed Google Play or keep apps in separate profiles

        [deleted] I need to for some notifications in my email as I'm forgetful And need the quick response times. I'd use tuta but I already paid for PM.

          Ratty I already paid for PM also but looking at the bigger picture that didn't stop me from switching. You don't have to take my word for it, but I know that the less Google (and other big names) on my device, the less I am visible to it and possible attack surface is reduced.

          Use protonmail in it's own "work" user profile. Allow notifications to alert on other profiles. You'll have to keep it running and switch over when you get an email. The cross profile alert will not show email sender, subject or anything, just that it's protonmail.

          It'll consume a bit of storage and maybe a bit more battery.

          Using a VPN to check either email or discord, or both, can be beneficial but not foolproof. It's an extra provider LE has to subpoena during an investigation. But also another provider that could betray trust.