This is just feedback and an Idea.

So I just did some reach search and found that Microsoft just updated Phone Link to support iOS texting. I think KDE can do the same by making a system where the phone connects to the PC via KDE Bluetooth and then on the iPhone you go to the bluetooth settings and you click the ℹ and you allow access to the contacts and notification. Then when some one gets a text on the iPhone, the iPhone send the notification data  and send it to the device (I think the iPhone thinks it a car or something like that) you can take that notification data and read the SMS notification and import them into the KDE SMS app.  and You could add a way two send messages back from the computer. Because currently. in the Beta of iOS phone link you can send text but not any attachments.