Need advice. The street dog in my neighborhood is getting more aggressive over time. How do I train a street dog to chill out?

Currently I am trying a make him relax next to me for half an hour to one hour strat even as things that frustrate him travel by and get him calmed down every time he gets growly.

I have already tried aggressiveness but that only makes him more aggressive and act out as well.

Disciplining appears to have him then refocus the pent up aggression somewhere else.

So the only recourse seems to be to teach it to mellow out.

How should I go about doing this?

Neutering is also on the table. Should it be done?