Sara, thanks for your link to the bug on the XBee3 LTE-M RF Module. That is helpful to know that some of the issues folks have experienced were due to a known hardware bug. Do you know if the hardware fixed modules are available to purchase yet?
Also, regarding your concern about adding a manually soldered capacitor chain, your link describes why it wouldn’t be a good idea using a breadboard, or probably even the SparkFun Breakout Board for XBee Module, because the power traces are undersized to transmit those short bursts of high-amp power. However, it seems that manually soldering capacitors into an appropriately-sized power line would likely work, right?