Is there a setting for trills w/ accidentals to always show the accidental by default?
I don’t believe there is. But after you’ve entered all of your music, you can select everything, filter for just ornaments and trills, and turn on the accidental.
If some of your trills already have accidentals forced on, then after you have them all selected, you’ll need to first toggle the Accidental property off, then turn it back on and select Show.