VBA scripts. I have a friend who works in the radio/telcom industry...but ends up doing a bunch of other stuff. This friend makes extensive use of VBA scripts to get the job done. You can't do that on the web version, and you can't do it in Calc.
Word is just for document interchange. Other businesses and clients use Word documents, and they don't display reliably correctly in any other program but Word.
The concerns about AWS servers are around metadata. If metadata were not a concern, why not just use Whatsapp? They use the Signal protocol so messages are end-to-end encrypted by default, and most people already have it or are willing to download it as compared to Signal.
Stable or development branch?
I don't see a problem with this business model. They're doing work maintaining software they don't want to maintain, so charging for it makes sense. It's surprising to me that Windows doesn't already charge a yearly subscription fee for OS upgrades.
Many people aren't going to pay the annual fee and will keep using Windows 10 without the security patches anyhow, so obviously this will weaken a lot of people's security, but, well... Microsoft needs to make money. And it's not like they need to worry about their customers defecting to another operating system. You can't just download and install macOS on an old Dell machine. If they're going to buy a new computer, it makes sense to get a less expensive one than what Apple's offering, ergo they'll get a new Windows 11 computer.
And if they wanted to and could use Linux...well, they'd already be using it. Overall, I'm completely nonplussed about this announcement. If you weren't going to pay Microsoft money, nothing has changed. If you need a longer support period, you now have an easy option. And hey, there's always the chance Microsoft will backtrack and provide free updates anyway. Especially given the lack of details on pricing, it seems like they're sounding out the idea rather than fully committed to deploying it.
It's worth mentioning that Android Auto doesn't work on GrapheneOS due to the privileged access it requires, and will not support it unless it is re-architected. Which phones were you thinking of when you said "compatible"?
I usually don't mind when most packages get behind, but the one I always notice is GNOME. It's been taking longer than I would generally expect for Arch to ship a new major update for GNOME. Fedora seems to have more up-to-date packages in most areas and ships them vanilla like Arch, as well as coming with a host of other sane defaults, so I've been thinking of making the switch...soon.
I don't use Microsoft Office, but I use Adobe. If the people I collaborate with or I work for use Adobe and need to edit my files, I'm not going to give them something done in Scribus instead of inDesign. That would be doing a bad job and also limiting their choices significantly with who they can go with in the future to edit their files. Same principle applies to Microsoft Office.