I'm sorry to hear that your friend is struggling to find a long term partner. When I think about dating apps, they are mostly about cold introductions. If possible, you should try to do some warm introductions from her. It seems easier to break someone's heart with shitty behaviour from a cold introduction, than a warm introduction. Cold intros are relatively anonymous so you can hide after your bad behaviour. With a warm intro, if someone does something awful, their friends will probably learn about it.