LR mobile doesn't support?
Got it. Yep, LR mobile does support it (I just downloaded an M50 file, added it to LRCC desktop and then opened/edited it with LR mobile). However, Apple Photos doesn't seem to support it yet, and photos uploaded to the phone/tablet generally have to come in via Apple Photos, so that could be a partial roadblock for you for now.
My Moto G5 plus is running nougat 7.0 and LR mobile for Android will not recognize CR3 files. It will load jpegs and will load CR2 files from my other Canon's. More of the same with LR mobile for IOS on my 5th gen iPad. I have the latest updates for Android and iOS