Bleach: Thousand-Year Blood War has been promising that the anime will be showcasing new materials that never made into the original version of the final arc from Tite Kubo's original manga, and the newest episode made good on this by giving Uryu Ishida a brand new form that just made its debut in the anime. The beauty of retrospect with Bleach: Thousand-Year Blood War is that the anime is allowed to finally adapt the final arc from the Bleach manga with the knowledge of what did and didn't work the first time around. Kubo's been involved with the new anime's production, and has been since adding new materials to better flesh it all out.
Ahead of Bleach: Thousand-Year Blood War Part 3 - The Conflict's debut this Fall, those behind the scenes of the anime had been teasing that there would be even more new forms, powers, and fights not seen in Kubo's manga. This was fully realized with the newest episode of the anime as Ichigo Kurosaki and Uryu not only had a fight that wasn't in the manga before, but Uryu even unleashed his full version of the Quincy's Vollstandig form power up that had never been seen in the original series. So it's brand new for the anime and franchise overall.
Bleach: Thousand-Year Blood War Episode 30 continues Yhwach's attempt to completely kill the Soul King, but Captain Ukitake's attempt to keep the Soul King grounded with Mimihagi has slowed down the process. Ichigo attempts to jump in and stop Yhwach, but Uryu quickly jumps into the mix. It's here that he and Ichigo start a new fight, and Ichigo can still tell that Uryu is likely holding back despite the fact that his being a Quincy means he's an enemy to the Soul Reapers.
But Ichigo's words fail to connect, however, as Uryu's power only reveals itself more through the fight. After being previously teased when he was using Antithesis for the first time against Squad Zero member Senjumaru, Uryu brings out a full pair of wings with his Vollstandig. It's yet to be fully named, but it's design seems to emphasize the kinds of straight and puncturing arrows that Uryu has been firing this whole time. It's such a power up over his previous form that Ichigo loses to it pretty quickly after Uryu activates it for the first realm time.
This was the form that Uryu was struggling against before, and could be a reason why he's tied so closely in with Yhwach. It's clear that the villain's power has control over all of the Quincies (even going as far as having control over the blood inside of Ichigo's body), and Uryu might have joined their side as a result of this. Still, that's pretty hard to tell right now as he was clearly not holding back in the slightest as he and Ichigo were coming to blows. He even eliminated Ichigo himself.
His new form has made him so powerful that he quickly pierces Ichigo with a massive hole in his body before the episode comes to an end, and it's likely he'll be doing even more damage before his real goal is revealed. Coupled with his new Antithesis power that bounces back all of the damage he takes onto his opponent instead, and Uryu might currently have one of the strongest sets of powers in action right now. That means now fans need to keep a closer eye on Uryu than ever before as these final fights in the arc continue.