Check your local Craigslist or other classifieds for cheap old GPUs. Or if you have another PC, borrow the GPU and power supply just to get it to boot.

Might be rebar or other reinforcement in the wall. See if you can shine a light on the hole and see what you are hitting. You might have to vacuum or blow the dust out first.

https://pcpartpicker.com/products/cpu/#sort=tdp&page=1

If you read the little summary, the test drive was in north Africa.