Help with skipping chain

Hi folks,

I'm getting terrible chain skipping on my bike.

It started when I changed my chain (KMC X10 Chain Silver/Black to KMC X10EL Chain 10 Speed Extra Light). The skipping was terrible so after some research I changed the cassette (Microshift Advent X before and after). I also changed the derailleur as it was a bit damaged after a fall (again Microshift Advent X before and after).

The skipping was still there, maybe slightly better. So I changed the chainring (e*thirteen SL guidering 36T before and after), but the skipping persists.

I don't understand what else I can do. All I've changed is the chain to an extra light chain, could it be that? I've checked the compatability and don't see why the EL chain wouldn't work.

I've attached a video to see the set up. It doesn't skip on the stand, only under pressure when riding. Changes gears ok.

Please help me!