How to lightly dull the sheen of latex acrylic paint touchups
You can try adding matt finish powder.  It is not noticeable in color and reduces the shine of paint.  The tough part is the level of shine so start small in adding the matt powder,  then do a test paint and allow to dry.  You must paint this indoors on your tests so get some drywall pieces and if vertical walls, stand the test piece vertical.  Horizontal dries faster than vertical and will affect the test of how much matt powder to use.  Then add more or less for the shine with each test.