I'd certainly publish a guide and a set of files to flash.
Using an internal Qualcomm SDX module, I've already got both 4G and 5G working great on my Thinkpad with just a few AT commands, so I don't foresee any practical difficulty except maybe getting MLC03 submmWave antennas (I can't find any, so I stick to B71 on 5G)
We seem to have very similar interests; if you want I can let you know when I release that (though it'll be nothing very complicated - just a few scripts to send and receive the right AT commands, along with a small README explaining how to provision the module with the right settings for your provider)
Been working on a pi400 eink solar powered cyberdeck but haven’t done anything with cell connection yet.
So could follow long for that and for the blackberry.