Well, you can always replace the firmware which is on the STM32L0 
(I believe this is what @onehorse/@GrumpyOldPizza are doing on their devices: they run everything in the Murata MCU)
Now I don’t think the Arduino is that bad…
- I don’t have any issue with downlinks on my side
- ADR is a special thing, but it kind of works: if the first packet is sent with a confirmation request, it will adjust the datarate for the following packets. It is somewhat limited as the datarate won’t be adjusted afterwards…
- It is also quite stable: I have one running since 215 days sending a packet every 5 minutes (>60000 packets) and it never resets.