Wii2hdmi squishes image on 4k TV but normal on original AV cables

Does anyone know why my image looks squished with the Wii2hdmi adapter? The first 3 pictures show how the Wii shows up on my tv. I have it connected to a 50 inch 4k onn Roku TV and idk if that's the reason it looks squished like that. The fourth picture shows how my Wii normally looks with the original AV cables, and the fifth one shows the Wii2hdmi adapter I'm using. It's unbranded so who knows how it was made or who made it. I just wanna know if this is normal for anyone else? Thank you.