Below code is helpful in providing list of weekday dates and can be used in dynamic filters

var num = 7;

var dateList = [];

for(var i=0;i<num ;i++){

var date = new GlideDate();

date.setValue(((''+gs.daysAgo(i+1)).split(" "))[0]);

var day = date.getByFormat('EEEE');

if(day != "Saturday" && day != "Sunday"){

dateList.push(date.getValue());

}else{

num ++;

}

}