There is a tapping noise coming from somewhere in the engine

Can you get a recording of this noise? It sounds like a possible wrist pin issue inside the engine. This is the pin that connects the piston to the connecting rod so if this is clicking then it would fit when you are hearing this. Hearing the noise will surely help identify it.

Here is a guide that helps with these types of noises but again, hearing the noise is the best next step because what I am thinking is an internal engine noise and is really only fixed by replacing the engine.

https://www.2carpros.com/articles/vehicle-scraping-noise

Let me know what you find. Thanks

Just to confirm it was the rapid tapping noise that you heard in second video when you were coming just off idle?

If this is the case that would be a bearing noise. With this be a diesel they are a noisier but that rapid clicking is a sign of a bearing noise. I would drain the oil and put it through a coffee filter and see if there is metal flake in it.

https://www.2carpros.com/articles/how-to-change-engine-oil-and-filter

Let me know what you find with this.