It's one of the reasons my next phone will be Android (with a non-spying custom ROM) instead of an iPhone. Although KDE Connect is already surprisingly powerful on the latter given the limitations of the platform.
The sheer amount of utility Connect has on iOS is insane. It’s starting to compete with handoff and iCloud sharing with how many features they’re recreating.
I prefer graphene personally but not gonna shill. I've dailied both but they are both great. Calyx has a bigger emphasis on free software while graphene has a bigger emphasis on privacy, but you can still achieve most FOSS calyx software on graphene as well.
Graphene is better in every way objectively speaking. Calyx came at a time where Graphene did not have sandboxed Google Play and had many compatibility issues. So Calyx was a middle ground between Lineage and Graphene. However, ever since Graphene implemented sandboxed Google Play, it has every edge over Calyx besides the freedom ideology where Calyx usss MicroG instead of sandboxed Google Play. Despite that though, I would still push you towards Graphene as Calyx has a history of falling behind security updates for weeks and even months.
Also from personal experience, I don't even use the sandboxed Google Play services on Graphene despite using a good bit of proprietary apps. You just won't receive notifications from applications that rely on it. But it does not really matter to me as I still receive notifications on Signal and Telegram FOSS, as well as obviously phone calls and SMS just fine.
I prefer grapheneos and have ran it for some years now, but I would prefer to stay out of that debate as the calyx community and graphene community do not like eachother.
Like, even mentioning them in the same sentence will get both of their police on you and start a flame war.
As a Graphene user I will admit that the community is somewhat disapointing, and the whole war between the two started because of the Ex leader of GrapheneOS Daniel Micay. Louis Rossmann and Techlore have videos about it. Hopefully the communities become more supportive of each other since Micay stepped down.
at least CalyxOS does support older Pixel phones aswell as the Fairphone 4
of course from a security standpoint older Pixel phones are less secure but still way more than outdated stock android while also saving on ressources (money and ecological wise)
it's not complete black and white, there are nuances between which favors one over the other