Ex boss hates me I think. Need advice

I'm a young professional (late twenties) and I left my previous job after being put on a PIP (Performance Improvement plan). I worked at the company for 1 year and 3 months before things took a turn. Everything was going well the first 6/7 months - I was paired with a trainer and we got along just fine. The new trainer who took over was one of those annoying listen to all my problems type of individuals.

She spent most of her time talking about her daughter getting bullied in school, how brave she is for being lesbian, how talented she is etc. She would train me but it just felt like she was spending most of her time talking to me like I was her therapist. This along with not having a monitor (I was working off a laptop and actively looking for a monitor) affected my performance but I wasn't signed off on anything I was still in training.

My boss sent me an email at the 1 year and 2 month mark saying ive been placed on a PIP and I have 4 weeks to put myself back on track and show results. I even asked him if I could be assigned a new trainer but that didn't work, he wanted me to be stuck with her. The trainer would even show me signing off messages she sends to other people around canada that she has trained as a way to show me she isn't the problem. This trainer went behind my back and told my manager that I sound very defensive in emails and she told another trainer at the company that which led that other trainer going to my boss and saying the same thing.

When I asked my trainer about this, she denied it and said she didn't say anything like that and started throwing smoke bombs to shift away from the question. 1 week after being on the PIP, on a Monday morning, I brought all my stuff to the office and quit. My manager called me and said he felt blind sided and would like for me to go home at least for the day before making that decision. I basically told him I understand him via his email about the PIP "loud and clear".

As weeks went by after, I had coworkers deleting me off of LinkedIn. I'm still connected by manager but when I posted that I got a new job at a major big bank in the country, I didn't get a single congratulations. However, when I saw an old colleague who worked for him post that she's been promoted at the company she works at now, he showed love.

Throughout my entire time working for him, he would joke about firing me and I kind of just shrugged it off since everything was going well and my first trainer never complained about me. She even told him how good I was doing. Advice ?