iMac-Qnap-NAS Network Setup

Hello Guys,

I am new in this network setup think so please bear with. If you have a suggestion please and expect to explain it very plainly so an idiot can understand it. Thank you :)

So I got a iMac 27" Retina late 2019 with the latest software update and I have a Qnap TVS-672XT NAS

I trying to setup a network connection between the two and at the moment I cannot figure out where is the problem. I just assume it is something with the Mac.

So my NAS is connected to my router ad it supposed to share the ethernet to my Mac via it network switches.

I assigned a static IP to the ethernet port what is connected to my Mac and I assigned the same IP to my Mac ethernet connection. Both device shows green connection, but when i turn off Wifi I got no internet on the Mac

Where should I go from here???