Can someone help me identify What is causing this sound

So I can feel the vibrations from this sound even on my Handlebar and I thought this sound was coming from bottom bracket, so I went to local shop and they suggested to change my bottom bracket along with chain and pedals as they all were in bad shape.. but still the sound continues and the local shop cannot figure out the reason..

Earlier I used to have these sounds and changing Crank Arm on left side used to be helpful in every two or so months but I would like a more permanent solution..

Can someone help in figuring out the source?? Thank you in advance..