A given SX125x radio chip has distinct RX and TX RF ports.
In the typically design, there is an RF switch that connects the antenna to either the RX ports of both radio chips, or the TX path which is the TX port of one radio chip followed by an amplifier.
So it’s not the receivers are so much “disabled” during transmit as that they loses their antenna.
I’m not 100% sure, but I think that when I had gateways transmitting occasional packets on uplink frequencies (with the idea that their peers would pick these up), they would occasionally receive their own transmissions - something that would be logical because even with the switch set the other way, there’s still going to be some energy leakage, and LoRa is designed to work with weak signals.
Unless you node is basically sitting next to the gateway, reception would cease and the low level packet CRC would fail even before the LoRaWan MIC.
Seeing if it is possible to get a node close enough for the received signal to be coupled even with the antenna switched the wrong way would be interesting, but relatively meaningless.
There’s an additional problem, too: buildable radios do not have perfect output on a narrow channel, but rather there’s some weak leakage, not only at spurious frequencies related to the design, but at close-in adjacent frequencies as well. I’ve found that if I have a distant node, and also a node very close to the gateway, if the close one transmits on the same time at a different frequency it will still manage to blank out the distant one. So even if it weren’t for the T/R switch, if your downlink frequencies are close to your uplink frequencies (iirc not all band plans keep them distinct) and even if the receiver had sufficient blocking dynamic range, this bleedover could still make reception during transmission not work.