There seems to be some confusion about "scaling" here. Rextroy vid was about
PvP scaling, a game mechanic implemented in BFA to replace the infamous
Legion PvP template system. Basically, in Legion your gear stats didn't matter in PvP, everyone had the same fixed stats which were given by your iLvL. Implemented to "balance things out" between ultrageared hardcore progaming players and filthy uncommited casuals, the Legion PvP system felt too rigid for minmaxing / customization purposes and was replaced with the current one.
BFA PvP scaling "even the odds®" between people when iLvl threshold is too high. For example, Johnny Mythic has 500ilvl and really wants to kill Bob Casual sitting near him, AFK'ing in Uldum near some rare spawn like the true casual he actually is. Problem: Bob Casual, being an absolute 2 hours a week player, has only 300ilvl. That 200ilvl threshold is too high for decency and fairplay purposes, that's when PvP scaling kicks in: a not so elaborated formula will make Johnny Mythic hit slightly less on Bob Casual, while Bob Casual is gonna hit Johnny Mythic slightly more, damage wise (it's more or less the same with heals). So, instead of being obliterated in one or two shots, Bob Casual will have a fighting chance (if he comes back from being AFK, please follow). This system works well with high iLvL thresholds; if A Player with 475iLvL hits B Player with 480iLvl, then scaling here is almost non-existant.
There's a lot of debate to whether this system is good, bad or the worst thing to happen to mankind alone, but please be aware PvP scaling, as its name strongly implies, only happen during PvP (Player Versus Player) interactions. It had nothing to do with PvE combat or leveling.