Shadowlands is just not compatible with WM.
In 9.0 the Maw heavily punished using WM because you lost Stygia when you died. And you needed that Stygia.
Outside of that reputations and world quests are not used for anything but cosmetics.
We didn't even have a weekly Call to Arms quest, until 9.1
Korthia is just badly designed for WM, it's a small linear zone without flying so based on any given daily activity there are many many choke-points to camp.
Also, there is nothing to use WM for outside of the Call to Arms quest.
In BfA you gained extra Azerite (direct player power) and extra war resources that you could use to gain more power with the war table. Also you gained free conquest for doing the invasion world quests in War Mode for easy weekly pvp items on alts.
In Shadowlands Anima does not give you power and the covenant table also is very lacking in meaningful rewards. All I use it for is to get augment runes, I hover around 70 constantly, nothing else. That will even be worthless once 9.2 comes with the infinite augment item.
I have not seen what Zereth Mortis is like or what rewards you can have. But the fact that we get actual WQ's might make it worth to farm more rep initially.