it looks to me, that in seeed lora e5 there is no discrete SEMTECH chip but some RF on a mixed signal CPU by STM, - with the problems of mixed signal noise reducing RF performance.
data sheet Lora E5 says -136dbm RX performace, but RAK11720 says -148dbm. If that is true then RAK reaches 4 times as far ( 26db= 2doubledistance free field). Is there an independent benchmark somewhere ?