I only use that combo now for single temp sensors, throw-away devices and canary applications. It works and it’s less than a tenner (£10 GBP) in parts.
For co-development of a POC I use a RAK4200 module with Arduino so the client can use the resources online to build something without worrying about the MAC.
For an actual device, the RAK4260 is pretty neat - a ATSAMR34J18 - Cortex M0 exactly as you suggested.