[eptcyka]

The routing table won't get flushed in between the slumber of the WiFi or 5G modem. You do not have to care about IPs or interfaces being up - we just need to synchronize network work so that most comms can be done in short bursts and then everything can go back to sleep. iOS does this, has done this for years.

[WesolyKubeczek]

Can't you hook into NM and provide the missing bits with scripts? Or do you need also to listen to "something else" to get the events like "the modem just went to sleep" which is not quite the same as deconfiguring it?

(I think no wonder those pieces are missing, it usually isn't happening on computer-shaped things, more on embedded- and phone-shaped things.)