For me, handling .tar files and not getting notifications would be a negligable price to pay for >tripling the number of people I’d be able to talk to, and more-secure installs. (I would now also lose the experimental calls functionality, but I haven’t actually used it yet, and text-only is better than nothing).
I already do not get notifications unless running the app, and honestly I turned them on for user testing, not because I want notifications. Nor will a Linux OS aggressively kill background processes and require I use a proprietary centralized notification service.
Correct me if I’m wrong here, but I think I could create a new profile on my new device, connect it to a profile on my old device, and send the tarfile E2EE. That doesn’t sound too hard to do manually. Using this method, I could also Reverse the "Add 2nd Device" flow or not, trivially, since either device could scan the QR code on the other.