[standard] Dimir/Sultai mill in a post vivi world

Full disclosure: I have not played 60 card formats in a serious form before, and looking at mostly FNM/Standard showdowns, with 8/10 locals of various skill/budget levels.

Looking through various youtubers and mythic players grinding the ladder, I keep seeing variations of mill using [[Riverchurn monument]] and [[Singularity Rupture]].

Pros:

• Seems to be a turn 6/7 win (depending on ramp) with singularity turn 5/6, in to riverchurn exhaust turn 6/7
• Land base is currently reasonably good with 2x4 shocks
• Has decent side board options with access to duress, enchant/artifact hate
• High card draw/card selection
• If holding mana for counter spells, hard to prevent riverchurn exhaust activation after a rupture

Cons:

• Doesn't have huge board presence
• Most lists have no plan B, if RiverChurn doesn't happen, you're stuck twiddling thumbs
• Probably gets walked on by other control lists to counter rupture/riverchurn combo

The two lists I can find tested in best of 3's are:
Sultai mill by Underdog: https://moxfield.com/decks/8y0GXDAsvkWh8-lVS8okig
and
Sultai Mill combo by Shahar Shenhar: https://mtga.untapped.gg/decks/AAQAAQaMBQGizSzP7gSLEM_8BgeH2C3kA9s4mATfuQek9gKIAwSHBbnYLfA39qUSB4dkrocB4eszvPUCtgv83gfVAwACBdEFggznqgH1lSufigEDv4AtoNAEmPoGAAGkLgADAtMR56oBAd_QMQGkLgAAAA

I have enjoyed control through dimir before rotation and enjoy the long game, these lists look interesting, but wondering on the thoughts of others, in case this looks like a gimmicky dead end that is easy to curb, before I invest on paper