I went to counselling years ago and an exercise I was given to deal with the rage and resentment I felt towards my MIL was to write a burn letter. I don’t know if it would benefit you, but I personally felt a huge catharsis in putting down every slight, comment and insult on to paper along with the associated feelings of hurt, anger and resentment they had caused me. Then I had a wee bonfire with it (and a nice glass of wine).
The first step for me was realising that the forgiveness was for me, then I worked on letting it go via the letter.
The type of person my MIL was meant that I would never be able to have a constructive conversation and get out all these feelings, so the letter was a way to do it.
It may not work for you, but I certainly felt a weight lifted. I wish you all the best in getting back on an even keel however you go about it x
How do you acknowledge Easter.