I've heard (but not tested) that Tahoe and iOS 26 do a _much_ better job of auto-connecting and reconnecting (if your cell drops, like going through a tunnel or similar) to make it easier to use your phone with your MBP.

I hope this is the case. I don't know if I would buy a cellular MBP (just wouldn't use it enough) but better tethering is a huge win for me.