Its still bad airflow I had similar pc case and I also place fans inside but it didnt help enough, and sharkoon do not have quality fans, own couple of them they are to crappy and to loud, maybe just me.
Bcs AMD GPU you need good airflow PC case and I could suggest you this one https://www.newegg.com/Product/Product.aspx?Item=N82E16811119346
This case is really good for money Airflow is great you can mount 6 fans 120MM or 4 140mmgood quality for money.
Am not fan of that RGB light show But you can get couple fans for 40$
https://www.newegg.com/Product/Product.aspx?Item=9SIAADY44C6758
Spare 10$ more and you have it and later you can mount one more fan Do not be cheap if you want OC
But if you really want cheap then go this one
https://ark.intel.com/content/www/us/en/ark/products/65520/intel-core-i5-3570k-processor-6m-cache-up-to-3-80-ghz.html
You can run K version without even OC, but I would suggest you, try to sell that CPU Motherboard and Memory and get some money to buy new generation.
People always try to go cheap on Power Supply Unit, and cheap can be so expensive. First even if you get any sort off good PSU you will at least fast get coil whine, in worst case you can kill your whole PC :).
Is it worth buying this GPU cooler, is it cooling whole GPU bcs I dont think so. As I see it it cool down GPU chip but not rest of GPU like memory chipset.
https://www.arctic.ac/eu_en/ax4.html