Although the Tiguan and Kodiaq are based on the same platform from the same group the build quality and materials do differ, with hindsight I’d have a VW over a Skoda even if the spec was slightly lower. Also don’t forget the Kodiaq is significantly bigger, depends on where your priorities lie.
Certainly in the past there was always a noticeable step up in quality from Skoda to VW, but I’m wondering if that’s still the case? I haven’t looked at the new Kodiaq in the flesh, but the new Tiguan has definitely taken a step backwards from the previous generation model when it comes to interior quality. It wasn’t the worst that I saw though. That award goes to the facelifted Ford Kuga. The door cards on those are just shocking and it doesn’t get much better elsewhere in the cabin!