I need help with my new camera

So I had a Sony ZVE10 with the TT artisan 10 millet of two lens and the picture was superb quality and very sharp. I took a lot of pictures from my penthouse apartment of the buildings below and no matter how much I assumed I saw very clear and sharp pictures.

BUT I just bought a brand new Sony A7iii with the Viltrox 16mm F1.8 lens and it is not sharp enough. It is not as sharp as my previous camera and lens used to be. I am using manual focus and I have tried manual. Focus auto focus using tripod without tripod, but I'm not sure what's going on because when I zoom in the picture is not as sharp as it was on my previous camera, so I am not sure because buying a full frame camera at this expensive lens I thought I would be getting a lot better quality which I am not.

I have been shooting with ZVE10 for a long time so I know about all the settings and manual settings, but I'm not sure what's wrong or is it the lens? What's causing the problem? Is it the camera? What's causing the problem? What's exactly the reason why the quality is not the same