Yeah, my first thought after reading the article was something like, "so I guess everyone will have to start grabbing phone/SMS apps out of F-Droid now". Annoying, but not that big of a deal, and I suspect the replacements will be better anyways. Worst case, the community and/or individual ROMs just fork the old AOSP versions, which has happened before as Google abandons things.
Most ROMs I see just fork LineageOS, which has a dialer of its own built in already.
Theoretically you can run an AOSP GSI on your phone and yes then you do need to find apps on F-Droid, but I don't think anyone but ROM developers do that.
