I thought about this for a while and went back and forth.
In the end I’d keep the iPhone + watch.
I know my way around Linux well enough to set up an environment that suits me well. In some ways it’d be better as it’s more custom fit to me, in others pretty inferior but I’d get by. My current heavy VMWare usage would be unaffected. Evolution would stand in for Outlook but not very well. Pidgin + Sipe kinda, sorta works for SfB and Teams I can run in a Chromium wrapper. I’d be better placed for most of our product UIs that run in Windows or Linux and I end up running in Wine or a VM on the Mac. My big bugbear would be the rest of Office. LibreOffice et al simply do not reach good enough standards to reliably produce documents in our corporate standard. I’d need a Windows VM for those. I legally own a copy so that’s not the end of the world
Tablet, my second most used form factor after the Mac. That’s the tough one. I’ve used Windows tablets (very recently), I’ve used Android tablets (less recently but I’m sure much has changed in the last 2 years) and I’ve owned iPads since iPad was a thing. I don’t want to lose my iPad in this hypothetical but in the end I have to concede I can do my mobile tasks on a large iPhone and my desktop tasks on Linux. IPad is the middle ground.
In somebody's case = [countable, usually singular] a situation that relates to a particular person or thing.
(Oxford Learners' Dictionary).
In your case the emphasis is on "Learner".