Build a new computer honestly.
Buy a cheapish case, 50 bucks, that allows for actual airflow. Buy some cheap fans, some P12s would be cjeap/effective.
Buy a motherboard that's not 10+ years old. Buy a power supply that's not some SFF oem proprietary garbage. clean your filthy pc out I can see the gunk build up in the gpu.
I got a triple bridged pcie, a 24pin mobo, and an 8pin cpu cable for $82 off Etsy. 16guage paracord.
RaysCustomCables I think it was. Took a couple weeks as they are hand made in China but they are excellent cables and Cablemod wanted $97 just for the pcie...