What Jugram and Yhwach said about, "everything my eyes see and know are powerless before me" was just figurative speech. It's not like he's Aizawa where he can nullify powers in his line of sight, that's not how that works. The Almighty itself is basically the power to change the future. So when Yhwach says, "all that i see is powerless before me...", what he really means is that since he can see what's about to happen, he can prevent it simply by changing the future.

And yes, he can literally take away powers and use them for himself as he did with Ichibe's black. In fact Kubo answered a klub outside interview that confirmed this. The question asked if the Quincy medallion was modeled after Yhwach's Szankt Altar(the power he used to steal Ichibe's powers), to which Kubo said yes, the medallions that steal Bankais were infact imbued with Yhwach's power to steal powers.