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.

I use Koler for dialing: https://f-droid.org/en/packages/com.chooloo.www.koler/ and QKSMS for messaging (already recommended here).

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.

if QKSMS still exists, it seems like a good replacement for the messaging app. That's what I used when I used Android a few years ago.

It still exists.

F-Droid also has alternative dialers, so I don't see how this is a big issue.

QKSMS has not been updated for two years and has broken MMS support.

Do you have a suggestion for an alternative?

I use custom fork of AOSP Messaging (on local LineageOS/microG build) with some minor UI tweaks and bugfixes. I have tried all other messaging apps on F-Droid, but every single one of them was broken in some way (mostly regarding MMS support or notifications while in deep sleep) or was missing a key feature (like delivery notifications).

The problem with MMS is that there is no built in system-level support for the protocol on Android, and due to legacy of 3G network/WAP, the protocol is quite odd when compared to modern alternatives.

Simple Mobile Tools SMS is fine. Not spectacular, but fine.

I'm using Google Voice for my dialer... really hope they don't break this outright though. Have thought it would be nice to replace GV with a FLOSS option I can self-host, but every time I've looked into it, it feels like such a convoluted mess.