=Textjoin(",";true;IFERROR(INDEX(Filter(
        IMPORTRANGE("https://docs.google.com/spreadsheets/d/1MPCIXoBqguYu9oRnwQ2tfYMqY_vY4tS5dJzNF7by3aY/edit?usp=sharing";"'"&Cell("Sheet"; date)&"'!B1:S1");
                INDEX(IMPORTRANGE("https://docs.google.com/spreadsheets/d/1MPCIXoBqguYu9oRnwQ2tfYMqY_vY4tS5dJzNF7by3aY/edit?usp=sharing";"'"&Cell("Sheet"; date)&"'!B2:S40");Day(date))
        =job);course);"-"))
        

=Textjoin(", ";True;Filter(
        IMPORTRANGE("https://docs.google.com/spreadsheets/d/1MPCIXoBqguYu9oRnwQ2tfYMqY_vY4tS5dJzNF7by3aY/edit?usp=sharing";"'"&Cell("Sheet";date)&"'!B1:S1");
                INDEX(IMPORTRANGE("https://docs.google.com/spreadsheets/d/1MPCIXoBqguYu9oRnwQ2tfYMqY_vY4tS5dJzNF7by3aY/edit?usp=sharing";"'"&Cell("Sheet";date)&"'!B2:S40");Day(date))
        =job))
        
        
Filter(
        IMPORTRANGE("https://docs.google.com/spreadsheets/d/1MPCIXoBqguYu9oRnwQ2tfYMqY_vY4tS5dJzNF7by3aY/edit?usp=sharing";"'"&Cell("Sheet"; date)&"'!B1:S1");
                INDEX(IMPORTRANGE("https://docs.google.com/spreadsheets/d/1MPCIXoBqguYu9oRnwQ2tfYMqY_vY4tS5dJzNF7by3aY/edit?usp=sharing";"'"&Cell("Sheet"; date)&"'!B2:S40");Day(date))
        =job);course)
        
        
        
        
=Textjoin(",";true;IFERROR(INDEX(Filter(
        IMPORTRANGE("https://docs.google.com/spreadsheets/d/1MPCIXoBqguYu9oRnwQ2tfYMqY_vY4tS5dJzNF7by3aY/edit?usp=sharing";"'"&Cell("Sheet"; date)&"'!B1:S1");
                INDEX(IMPORTRANGE("https://docs.google.com/spreadsheets/d/1MPCIXoBqguYu9oRnwQ2tfYMqY_vY4tS5dJzNF7by3aY/edit?usp=sharing";"'"&Cell("Sheet"; date)&"'!B2:S40");Day(date))
        =job);course);"-"))
        
        
====================================
        
        
=LET(filtr;
            Filter(
                IMPORTRANGE("https://docs.google.com/spreadsheets/d/1MPCIXoBqguYu9oRnwQ2tfYMqY_vY4tS5dJzNF7by3aY/edit?usp=sharing";"'"&Cell("Sheet";A3)&"'!B1:S1");
                INDEX(IMPORTRANGE("https://docs.google.com/spreadsheets/d/1MPCIXoBqguYu9oRnwQ2tfYMqY_vY4tS5dJzNF7by3aY/edit?usp=sharing";"'"&Cell("Sheet";A3)&"'!B2:S40");Day(A3))
            ="surf");
            If(A1=1;CHOOSECOLS(filtr;1;2);CHOOSECOLS(filtr; SEQUENCE(COLUMNS(filtr)-2; 1; 3)))
        )



=Textjoin(", ";true;LET(filtr;
            Filter(
                IMPORTRANGE("https://docs.google.com/spreadsheets/d/1MPCIXoBqguYu9oRnwQ2tfYMqY_vY4tS5dJzNF7by3aY/edit?usp=sharing";"'"&Cell("Sheet";date)&"'!B1:T1");
                INDEX(IMPORTRANGE("https://docs.google.com/spreadsheets/d/1MPCIXoBqguYu9oRnwQ2tfYMqY_vY4tS5dJzNF7by3aY/edit?usp=sharing";"'"&Cell("Sheet";date)&"'!B2:T40");Day(date))
            =job);
            If(course=1;CHOOSECOLS(filtr;1;2);IFERROR(CHOOSECOLS(filtr; SEQUENCE(COLUMNS(filtr)-2; 1; 3));"-"))
        ))