How to Maximize Winrate in Low-Level BGs?

I last played in 2011. I have kids now who have started playing WoW. They love Battlegrounds but they’re little, so get stomped. I’ve been reading that twinking is largely gone (Principles of War, gear scaling, etc).

It looks like one’s item levels still matter. Is that true in low-level brackets? If I convince my kids to grind dungeons for blue items will that give them a leg up? Any other advice is welcome, too!