2000 Jaguar XJ8 Engine Knocking Noise

I had knocking noise and checked the oil and turns out that there is almost no oil left in the engine. It was basically dry. There is no leak so it is probably oil consumption but major issue is this knocking noise

Got synthetic oil changed but the knocking noise is even worse.

The light never came on before I replace the oil which is odd, after the oil change I got this message on and off : low oil pressure

Ideas are the oil pump is messed up so it can not pump the new oil into the engine..
some people say tensioners may be messed up..

What can be the problem, How can i get it fixed, what do you recommend?

Thank you for the help.