Looking at Ultrabooks currently its very hard (even as a long term Windows user) to ignore the M1 Macbook Air; its the right size, the screen is great, the power is unreal and the battery life looks incredible.
However despite trying I'm not ready to fully move over to a full Apple ecosystem; I've got an S21 Ultra (less important) but also a Galaxy S7+ tablet.
I guess my main worry is cross-compatibility of things like being able to sync notes and documents.
Are there others out there with a similar mixed eco-system? How do you get on with it?
Let me try and answer this from a different perspective.
Even though I own (and love) my M1 MacBook Air, my
main OS of choice is Linux Mint. There is a useful comparison to be made here because Linux Mint is just as much
not Android as macOS is.
You need to get software (I know I found and installed something on my MBA but I can't remember exactly what it is at the moment) but I think you can also download Android File Transfer from Google. It goes without saying that MTP (I think that's what Android uses) is built into most mainstream Linux distros, and of course LM is no exception.
As far as "synchronization", I don't really believe in going down that road. I'd much rather use centralized cloud services (in particular, Google's office suite) to handle tasks I need to access from multiple different devices, and in part because this assures platform independence.
Because of my job, I make daily use of this kind of thing, particularly spreadsheet and calendaring functionality.
The only real time I need to connect my phone to my computer is to do things related to initial setup (adding sounds to the Alarms, Notifications, and Ringtones folders), etc. As my phone has a microSD card reader (whereas yours does not) I only need to add to the locally-stored music on an ongoing, as needed basis (and that is exceedingly rare).