Zwift only controls incline on one treadmill, the $5K Wahoo Kickr Run, (and I don’t believe that control is in the release version of Zwift yet).
The third-party app, QZ Fitness, is your only option for incline control. Zwift may have plans to expand incline control to other smart treadmills but I suspect not until Wahoo have sold a few units!
Sole S77 quality control straight out of the box… The nut that isn’t in the right place is welded on the back of the bracket… The QC passed sticker is 6 inches away LoL