hello and thanks,
yes I agree. Meanwhile I found the SX1262 data sheet as well which is contained in RAK discretely as a chip product and in Seeed integrated as on mixed signal silicon.
As you found out Semtech only archieves -148dbm when operating SF12 using 12.4KHz which is not relevant for most apps.
At SF12 /125kHz Semtech states -137db which is in line with Seeeds measurements. RAK cannot have more using SX1262, so I now think there is no big difference. I was wrong.
Starting from there, Seeed is the better solution for us, because RAK does not do LBT in EU868 mode. Seeed seems to do that independent of the US/CN/EU mode. Unfortunately details are not given wether that matches ETSI regulation for more than 1% air time duty cycle. … need to futher investigate.