It should make a noticeable difference. I doubt you can really go much bigger/brighter with the reverse lights given the type of light that can fit in there.

I also use the turn-as-tail mod here: https://www.amazon.com/Tail-Module-2014-2017-Toyota-4Runner/dp/B06XWZKDTB to make it even brighter. One of the things it does is to wire your turn blinkers into the backup circuit, so the turn bulbs go on at the same time when you reverse. Then you also want to replace the turn bulbs with LEDs, plus a resistor so you don't get the rapid blink.