2021 Toyota Tundra CrewMax, Factory Sub Replacement

Just purchased a 2021 Toyota Tundra Crewmax Platinum with the JBL high-end stereo. I am very disappointed in the Subwoofer in this truck that is located behind the Rear seat. My goal is to get the sub-base volume up (I do like a nice-sounding base), but not looking to shake the sheet metal on the truck, LOL! I'm looking to replace the sub with a Rockford Fosgate Punch class-BD 1-channel amp (P500X1bd) with remote volume control and an RF shallow mount loaded Subwoofer Punch P3S-1X12 shallow enclosure due to the very limited depth behind the rear seat. I have two installation questions being new to automotive sound systems.

1) The RF Punch amp puts out 500watts RMS at 1 Ohm but the Speaker says it can handle 400watts RMS at 1 Ohm. Since the Amp is rated for 100watts RMS more than the speaker at the same Ohm rating, is there any control I can use to keep from blowing the speaker? The next lower RF Punch amp is only 300 Watts RMS at 1 ohm so I'm a bit torn as to what is the right way to go. Under powering the speaker doesn't seem right either but I may be wrong. Is there any way to limit the gain or output of the 500watt RMS amp besides just not turning it way up? Or should I go with the 300watt RMS amp?

2) My plan is to use the current Subwoofer output of the factory amp to feed the new RF Punch amp. It says it can accept high-level inputs. But I only have a single pair of wires from the factory sub feed. The amp has right and left RCA high-level inputs. How do I wire up the factory single subwoofer input to feed the amp correctly? And on the output side of the amp, I have the same type of question. There are 2 sets of speaker outputs, Do I just use one of the two sets of speaker outputs to feed the subwoofer?

Thanks in advance for any help in wiring this amp and speaker correctly.

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Sobman