Thanks for this information. So, I made some analysis and yes, the KOT49H driver eats too much CPU but not in the same way as does the KTU84x.

With the KTU84x (the CM original driver), the driver eats CPU when it crashes.

The KOT49H didn't crash during my testing (I've switched to the KRT16M to see how things are going). I saw it eating too much CPU, but only when the phone was awake. As long as the phone is asleep, the CPU consumption is far from being significant. So, imho, that could be an acceptable tradeoff, because my N5 is asleep most of the time.

I'm keeping the KRT16M for a moment.