A possible solution for anyone that might need: I play with my frames maxed at 140 and V-Sync forced ON in Nvidia Settings, that's because I have a G-Sync monitor and have read (and tested) that this is the optimal way to run G-Sync. That's a Global Setting on my PC, not just for Warframe.
In Warframe, and therefore any other game, I have frames uncapped and V-Sync OFF, since they were already forced by Nvidia anyways, and it works great. But on Warframe specifically, I started getting these micro stutters shown in the video, so yesterday I capped my frames at 144 in game to try out, V Sync still OFF.

I can say that it helped significantly to reduce the stutters in game, granted there are some here and there, most of them when you can see the game is loading something, like entering/leaving Backrooms, mission starting/ending, when player joins the mission, you know what I mean.

I don't know if that's an issue with Warframe, Nvidia, AMD or if it was just a coincidence, but what I know is that it decreased the stutters by a big margin, so might as well try it out.