I try to remind myself that it is their problem, not mine, and try not to think about it. Of course, it isn’t easy since I am very into the concept of “kol Yisrael areivim..” and it isn’t easy for me not to feel bad for them. But once I realized that it is the right thing to do (imho), it was much easier. I can’t solve all the world’s problems – I can only do my best.
Also, during “hashiveinu” in Shemona Esrei, I say a Tefila for specific people I know to be chozer b’teshuva. I include all the people I am mad at and haven’t forgiven. I also include Yair Lapid and Bibi Netanyahu. I include all my not-Frum or OTD relatives and acquaintances. I include a lot of people who would probably be very insulted if they knew about it, but I make sure to put my name first so it doesn’t sound too gaavadik.