If you added 1.5 litres due to low level then that is a lot.
Check the level when the engine is cold. Checking a hot engine just after stopping will give a false low level as the oil will not have drained down.
Besides a low oil level and the possible wear it causes, how are your plugs and leads? Old leads could be starting to fail and temperature making them worse?
The noise in the video is certainly loud. What oil pressure do you have?
My 2002 touches 3bar when cold and on the move, dropping at idle as is normal for the engine. They don't run at high pressure.
