On the other hand, we focus _only_ on JMAP. https://www.ariamailclient.com
I wouldn't say it's something that can be vibecoded in a month or two. Proper design and implementation take time if you want to handle accounts with hundreds of thousands of messages seamlessly.
More importantly, which language(s) and UI toolkit are you using for your Linux app?
I Feel so entitled and spoiled when I write this…
These days with the convenience of having LLMs at developer’s disposal, it feels unjustified to use electron like apps.. whenever I see “one app all/multi-platform”, I feel discouraged to give it a genuine try.
I tried a bunch of email clients and then crawled back to mail.app + Calendar.app on MacOS simply for how native it feels.