Epilog: I hooked up the old receiver, with its external antenna, to the new mote, and it's not obviously worse for the wear:
12:23:12 May 18 2022
V1.0
104_LoRa_Receiver_Detailed_Setup Starting
LoRa Device found
SX1280,PACKET_TYPE_LORA,2444999936hz,SF7,BW406250,CR4:5
SX1280,PACKET_TYPE_LORA,Preamble_12,Explicit,PayloadL_255,CRC_ON,IQ_NORMAL,LNAgain_HighSensitivity
Reg 0 1 2 3 4 5 6 7 8 9 A B C D E F
0x900 80 FF 77 41 20 FA BC 13 C1 80 00 00 00 00 00 61
0x910 9C 44 00 00 00 19 00 00 00 19 87 65 43 21 7F FF
0x920 FF FF FF 00 70 37 12 50 D0 80 00 C0 5F D2 8F 0A
0x930 00 C0 00 00 00 24 00 21 28 B0 30 0D 01 51 63 0C
0x940 58 0B 32 0A 16 24 6B 96 00 18 00 00 00 00 00 00
0x950 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x960 00 00 00 00 00 00 00 00 00 00 FF FF FF FF FF FF
0x970 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF 04
0x980 00 0B 18 70 00 00 00 4C 00 F0 64 00 00 00 00 00
0x990 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x9A0 00 08 EC B8 9D 8A E6 66 04 00 00 00 00 00 00 00
0x9B0 00 08 EC B8 9D 8A E6 66 04 00 00 00 00 00 00 00
0x9C0 00 16 00 3F E8 01 FF FF FF FF 5E 4D 25 10 55 55
0x9D0 55 55 55 55 55 55 55 55 55 55 55 55 55 00 00 00
0x9E0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x9F0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
Receiver ready - RXBUFFER_SIZE 32
4s Hello World 1234567890*,CRC,DAAB,RSSI,-57dBm,SNR,12dB,Length,23,Packets,1,Errors,0,IRQreg,8012
8s Hello World 1234567890*,CRC,DAAB,RSSI,-55dBm,SNR,13dB,Length,23,Packets,2,Errors,0,IRQreg,8012
12s Hello World 1234567890*,CRC,DAAB,RSSI,-57dBm,SNR,13dB,Length,23,Packets,3,Errors,0,IRQreg,8012
16s Hello World 1234567890*,CRC,DAAB,RSSI,-57dBm,SNR,12dB,Length,23,Packets,4,Errors,0,IRQreg,8012
20s Hello World 1234567890*,CRC,DAAB,RSSI,-54dBm,SNR,9dB,Length,23,Packets,5,Errors,0,IRQreg,8012
24s Hello World 1234567890*,CRC,DAAB,RSSI,-52dBm,SNR,3dB,Length,23,Packets,6,Errors,0,IRQreg,8012
29s Hello World 1234567890*,CRC,DAAB,RSSI,-55dBm,SNR,11dB,Length,23,Packets,7,Errors,0,IRQreg,8012
33s Hello World 1234567890*,CRC,DAAB,RSSI,-55dBm,SNR,13dB,Length,23,Packets,8,Errors,0,IRQreg,8012
37s Hello World 1234567890*,CRC,DAAB,RSSI,-50dBm,SNR,12dB,Length,23,Packets,9,Errors,0,IRQreg,8012
41s Hello World 1234567890*,CRC,DAAB,RSSI,-53dBm,SNR,13dB,Length,23,Packets,10,Errors,0,IRQreg,8012
45s Hello World 1234567890*,CRC,DAAB,RSSI,-56dBm,SNR,14dB,Length,23,Packets,11,Errors,0,IRQreg,8012
49s Hello World 1234567890*,CRC,DAAB,RSSI,-53dBm,SNR,8dB,Length,23,Packets,12,Errors,0,IRQreg,8012
53s Hello World 1234567890*,CRC,DAAB,RSSI,-51dBm,SNR,3dB,Length,23,Packets,13,Errors,0,IRQreg,8012
57s Hello World 1234567890*,CRC,DAAB,RSSI,-52dBm,SNR,8dB,Length,23,Packets,14,Errors,0,IRQreg,8012
61s Hello World 1234567890*,CRC,DAAB,RSSI,-52dBm,SNR,12dB,Length,23,Packets,15,Errors,0,IRQreg,8012
65s Hello World 1234567890*,CRC,DAAB,RSSI,-52dBm,SNR,11dB,Length,23,Packets,16,Errors,0,IRQreg,8012
69s Hello World 1234567890*,CRC,DAAB,RSSI,-52dBm,SNR,13dB,Length,23,Packets,17,Errors,0,IRQreg,8012
73s Hello World 1234567890*,CRC,DAAB,RSSI,-50dBm,SNR,13dB,Length,23,Packets,18,Errors,0,IRQreg,8012
77s Hello World 1234567890*,CRC,DAAB,RSSI,-51dBm,SNR,13dB,Length,23,Packets,19,Errors,0,IRQreg,8012
82s Hello World 1234567890*,CRC,DAAB,RSSI,-55dBm,SNR,12dB,Length,23,Packets,20,Errors,0,IRQreg,8012
86s Hello World 1234567890*,CRC,DAAB,RSSI,-56dBm,SNR,7dB,Length,23,Packets,21,Errors,0,IRQreg,8012
90s Hello World 1234567890*,CRC,DAAB,RSSI,-57dBm,SNR,13dB,Length,23,Packets,22,Errors,0,IRQreg,8012
94s Hello World 1234567890*,CRC,DAAB,RSSI,-56dBm,SNR,13dB,Length,23,Packets,23,Errors,0,IRQreg,8012
98s Hello World 1234567890*,CRC,DAAB,RSSI,-48dBm,SNR,6dB,Length,23,Packets,24,Errors,0,IRQreg,8012
One thing I do notice,though, when reviewing the receive packet data, with both the new and old radios are considerable variances in SNR. The 915Mhz adafruit transceivers don't show much variance (see earlier post for the telemetry). I presume, therefore, the larger SNR variances are caused by environmental interference that varies over time in the 2.4Ghz band, or at least the default channel in that band chosen by the library.
The end!