Raimund Kohl-Füchsle <rk-f@posteo.de> writes:

 I do have a recurring task Mo-Fri, but not at weekends.

 I searched the manual and it offers a time range - like

     ** Test Time range

          <2004-08-23 Mon>--<2004-08-26 Thu>

 But, of course, this doesn't mark a recurring task.

 If instead I would use

     ** TODO Test Time range

          <2004-08-23 Mon>--<2004-08-26 Thu>

 then this for org-mode would just be one todo; if I mark it done on Mon 
 all other days are marked as done, too.

 So how would I schedule a daily TODO only, say, this week from Mo - Fr?

The way I handle this, which isn't particularly elegant, is to just have
a heading for each day of interest.  So, in your case, something like

  ** TODO task (Mon)
  SCHEDULED: <2019-07-01 Mon ++1w>
  
  ** TODO task (Tue)
  SCHEDULED: <2019-07-02 Tue ++1w>
  
  [...]

  ** TODO task (Fri)
  SCHEDULED: <2019-07-05 Fri ++1w>