[Nexus]

MC-XOBAHCK, попробуйте так:

document.querySelector('#shag3').addEventListener('click', function() {
        for (let i = 0; i < 50; i++) {
			(function(i){
				let name_function = 'brus' + i;
				let time;

				if (i == 0) time = 10;
				else time = 400 * i;

				setTimeout(name_function, time);

				console.log(name_function + ' и ' + time);
			})(i)
        }
    )
}