Limiting battery input current to avoid voltage drop when activating LoRa radio
A current limiter simply won't work - you can't get energy from nowhere, and causing the supply to &quot;brown out&quot; during transmit is likely to at best yield poor on-air results; more likely cause a crash and hopefully restart of the entire system.
To the best of my knowledge, all LoRa radio chips have programmable output power, so if you want to limit the power required from the supply, configure the radio to use a lower transmit power under conditions where the battery will be weak.
A sufficiently large capacitor could in theory be a solution if used with care; you'd probably want to charge it in advance of a transmit or receive operation.  Bear in mind that at the slower (larger) spreading factors a LoRa transmission may take several hundred milliseconds to (in places where duration limits don't preclude it) well more than a second.