A new screen and cable later and neither seem to have fixed the problem. The laptop runs perfectly except via the LCD cable. I have removed the new screen but the new LCD cable is still in place. No power adapter is included.
HP 250 G8 15.6" Laptop | Intel Core i3 | 16GB RAM | No SSD | Multiple Conditions
HP 250 G8 Notebook, Intel i5-1135G7, 8GB DDR4, 256GB SSD, Win11, 15.6" Laptop
HP 250 G8 15.6” FHD i7-1065G7 8GB 256GB SSD Win10 Home Laptop