I've replaced cabin air filter recently however, it still smells really bad.
I've seen some videos regarding how to fix smelly ac on youtube.
they usually spray lysol product on air intake vent. I'm not sure where air intake vent is located. is it located below wiper?

 

The intake is at the cabin air filter. You could try some Star Bright products that can be purchased at boat/marine supply vendors and possibly also Amazon. They make a fast release product. It is chlorine based so gotta be sure to have some plastic down where you place the bag.

You can also remove the filter and spray some lysol or a chlorine based bath cleaner in the filter box. Again, place plastic so if there are any drips it gets caught.

 

I know that if you do stuff in your driveway, it can be a bit tricky, but there's companies like Valvoline that makes A/C treatment products. One can being foam that you introduce from the a/c drain tube under the car, let it expand and it turns back into a liquid and drain itself out. It's meant to soak the evaporator and kill mold and crap on it.

It's probably the best thing to do first and if the feet smell remains after that, it might involve a bit more work. Sometimes evaporators can get really bad and grow all kind of not so great stuff on it. They're subjected to a lot of humidity, so when dust stick to it, water will stay there.