Reading the specs you posted, it says that the pcie x16 slot is occupied.
What is installed there?
The 3200g processor should be using integrated graphics.
I really think you are stuck.
The motherboard is proprietary and will not use standard ATX power supply connectors.
The case has minimal ventilation. A hot card will get no meaningful airflow.
Only one exhaust fan, and no intake that I can see.
Another problem will be how to connect the front panel to the case.
The front usb ports are exactly mated to the case.
Changing out the case will not work.
You could salvage the cpu, ram, drives and buy a new case,psu and motherboard.
I suspect that you would be better off to sell the whole package and build anew.
You can buy a stronger i3-10100, a lga1200 motherboard and 16gb of ddr4 ram for $250 or so.
https://www.techpowerup.com/review/intel-core-i3-10100/15.html