They do have e2e for emails. Any emails between Proton Mail users are always e2e encrypted, as are any emails others send you which they’ve encrypted with their own maio client. If someone sends you an email unecrypted (most email is), then Proton will encrypt it for you and put it in your inbox. They can’t read it after that, but there is some trust required that they don’t store/look at the unecrypted email before then.
The reason that Google got ruled against originally was that they were paying and offering incentives to developers to keep them from releasing their apps on other app stores.
Google also doesn’t support a user installing the Play Store themselves (and the required Google Play Services dependency). So phone manufactures have to choose to include it on everybody’s phone from the get go, or their users won’t be able to use it at all.