ties don't work in example submitted

Not sure what you're talking about, that sample score has ties all over the place, between all grace notes and the main chord

Same here (OS: Windows 10 (10.0), Arch.: x86_64, MuseScore version (64-bit): 3.4.2.9788, revision: 148e43f)
take a new score with piano (see attachement)
1) add a chord of 4 notes, add four 32nd grace notes to the highest note.
2) change the pitch of the grace notes by computer-keys
3) add a tie to note E (the problem is always the second note): the tie doesn't go to main note
4) add the other ties

5) try in the bass clef, add a chord of 3 notes
6) select the highest note and add a 16th grace note, select the second note add a 16th grace note, select the lowest note … add the ties
7) same with a chord of two notes and quarter grace notes