1×10, duraace 7900 cassette& Rderailleur, 4600SL trigger shifter, narrow wide 34t. No matter how much i adjust it, it slams into gear when downshifting. Enough for my foot to slip off. Btension makes it smoother downshifting but higher gears slam into gear. Its only when putting down powet. Advise!

Your chain looks too long.
Heck, with such a limited cassette range you might be able to get away with a short cage derailleur. But you’d still want to size your chain properly.

Your pedals look like some sort of skeletal flats, do they not have good spikes that keep your shoes stuck to them? Maybe consider clipless pedals/shoes?

Is hanger straight? How old is cassette and chain?

A few things:

– look up chain sizing, as someone else mentioned — two links is a huge amount to add. You need to run it around the big-big gear combo, then add two.

– if your b-tension is set too high (too far out), then your derailleur has less authority in the higher/smaller gears. Only try to be max 5mm away from the largest gear

– how straight is your derailleur hanger?

– is your chain worn? If it’s worn out, then it can flex away from the derailleur too easily

– check the derailleur for gumminess: tap the arm into the frame, then pull it back. If it has more room to settle than the spring pulls it away from the frame, then it needs to be cleaned. When the derailleur is gummy, the cable pulling while shifting towards low gears defines one set of shift positions, and the spring pulling back defines another, slightly offset position