DC voltage variation of LBR20 Orbi 4G

I have this same question as the voltage in my camp trailer can fluctuate between 11.5 and 13.5 voltage depending on SoC.  In my experience most DC operated devices can handle some fluctuation within this range, but installing a 12v regulator might not be a bad idea.  I plan to install one of these behind my exterior 12v receptacle (which is where I plug the LBR20 when I'm camped).

https://www.amazon.com/Converter-Automatic-12V-Waterproof-Transformer/dp/B07V8K6YZ6/

As to the comment regarding amps, this is irrelevant; a device will only consume the amperage it needs.  You can put a device that draws 2 amps on a 2,000 amp circuit and as long as the voltage is correct, it will make no difference to the device.  if however, you vary the voltage too much, it will pull more or less amperage based on the wattage requirement of the device (See Ohms Law for the basics).   For example, if the LBR20 requires 24 watts (12v x 2 amps) and you reduce the line voltage to 9 volts, the device will pull 2.7 amps which could exceed tolerances within the circuitry.  (think of it like increasing the water pressure in a pipe because you made the pipe smaller but still need to deliver the same volume of water; you can burst a pipe or fitting).