Irrelevant Backstory
apparently since i got the plasma mobile update in december that switched from ofono to modemmanager, cellular modem access on my pinephone has been broken and after not being able to quickly solve it and not finding anything on the web, i just left it like this for now since i rarely need cellular stuff and i plan to try other distros (with system encryption) and uis anyway and i assumed a clean os install would fix it.
but now my trusty nearly 10 year old sim card in my 12 year old phone seems to have been deactivated without notice. i dont have any documents about that ancient sim card that was purchased when anonymous prepaid sim cards were still a thing here, i dont even know the so-called pin identification number [sic], so having it reactivated or transferring the number to a different provider is most likely impossible. i took this as a sign to fix the pinephone modem issue and completely switch over. ill post details about (2fa) phone number switching once its been successful everywhere so you know what happens should you ever lose access to your number. if only i had already updated my number everywhere to the new sim card i got for my pinephone, but i wanted to wait until im certain that the pinephone and the sim card from some small provider (the only one with no deactivations for not adding enough prepaid funds that ill never use and with 200 mb for free each month!) both work reliably for 2fa purposes. and if only phone numbers werent mandatory for some services.
ofono seemed to still be working perfectly, while using any mmcli command thats not --help* resulted in an error like "the modemmanager process couldnt be found in the bus". so i guessed the kde applications now communicate with modemmanager instead of ofono but somehow the update didnt properly replace ofono with modemmanager, so the applications and the modem were basically talking past each other. in the logs i found "Activation via systemd failed for unit 'dbus-org.freedesktop.ModemManager1.service': Unit dbus-org.freedesktop.ModemManager1.service not found" and that ofono successfully started and brought the modem online. since i dont have much systemd knowledge, i assumed the service was missing and i somehow had to manually create it. reinstalling modemmanager(-pp) didnt change anything. but then, for the first time after many other web searches with no results at all, i found this: invent.kde.org/teams/plasma-mobile/issues/-/issues/62
Actual Part You’re Looking For
i couldnt believe that simply disabling the ofono process and enabling the mm process was all i needed to fix the issue all along, but it looked like what i need and it indeed worked. (re)installing mm-pp as in the first line might not have been necessary to fix this issue since i already had mm-pp, but i already used that command earlier anyway, so i dont know if it was a mandatory part to fixing the problem. but it works, and this is the solution, should anyone else have the same issue, though im apparently the only one since there were no web search results.