Assuming nextday is required, the following result was found.
a Sunday, and move the next few days along: thisDate = '2021-10-30'; v_Today = thisDate; v_Tomorrow = v_Today.addDay(1); v_NextDay = v_Today.addDay(2); if(v_Today.getDayOfWeek()==1) { v_Today = v_Today.addDay(1); v_Tomorrow = v_Tomorrow.addDay(1);...