Harassed By School Admin Until I Resigned. Should I Just Let This Go Or Seek Legal Action?

This happened a couple months ago and I'm willing to just let things lie. But I wonder if that's a mistake. I was a elementary school teacher at a public school in Arizona, and had been there for years.

The principal and vice principal were suddenly fired and replaced this year. Within the first three months of the new school year, over half a dozen teachers had resigned or had been fired. Then they came for me. There is no teachers' union in this district, so I had to stand alone.
I suspect the motivation was probably to reduce salary costs; As a 17 year veteran teacher, I pull a higher salary than a first-year teacher. However, I was a "continuing teacher" and could not be dismissed without charges.

Admin invented charges of unprofessional conduct and I had to prove my innocence. Then they filed an official written reprimand. The charge on the reprimand was different than was mentioned in the e-mail, and I used that to file a grievance against my principal with the school board.

It was a miserable month or two, being constantly harassed and spending a lot of time fighting false accusations. Then some female students started accusing me of stalking them. They had been caught trying to leave school early on three occasions and never forgave me. As a male teacher, I realized I could lose my house, my career and my freedom trying to fight off legal accusations so I e-mailed admin about the issue and gave three options: Immediate change to another school in the district, an aide for eyewitness protection, or resigning my position without penalty.

Admin jumped on the "resign" part. I showed up for a post-observation conference but was given a resignation form to sign. I was off-campus that afternoon. I was allowed to gather my stuff from the classroom a few days later.

I've never checked up on the grievance. I figured the admin was following a directive from the school board and the grievance would just get thrown out.

I'm now teaching in a better school and figured the past is the past, and there's no sense in pursuing legal action out of revenge.

But should I? Is there any legal, moral, or financial reason to pursue legal action against my former school district?