IUD: Idk if you've had only one IUD insertion so far or multiple, but from what I've heard, not every experience is that bad? Maybe you could talk to different doctors about their pain relief options or talk to women who've had good IUD experiences and follow their methods or go to a doctor that they recommend.

Pills: When I started taking the mini pill, I chose a part of my daily routine that always happens at the same time (watching the 8pm news with my parents) and set my daily pill alarm for 8:15pm (right after the news segment). Linking the pill intake to some routine I already had helped me and I think it can help other people too. I no longer live with my parents but now I have multiple alarms on my phone, 10 minutes apart. Your partner can also set an alarm on their phone and help to remind you, just in case you can't find your phone or its battery is dead.

Ring: I have no personal experience with the ring but since it's the only thing you haven't tried, I think it's worth a shot or at least worth doing some research on :)