I'd walk away. There is a point where health and sanity is more important than chasing some bad actors. You are also likely screwed on workplace issues, in CA I believe it is 1 year from the date of the alleged harassment, threat etc. This is pretty common across most states, you have to report it quickly.

As for the equity, even if you sue and get your small percentage of equity they would just have a board meeting and create a different share class which in the end will dilute you to nothing (if they haven't already). Only thing that might change my thinking here is if they put in writing you had > 10% or non-diluting or something similar, then maybe it might be worth a little time with an attorney.

Also, you said you tried to hire an attorney for workplace violations, if you spoke with an attorney and they didn't take it then likely you didn't have a provable case. Not saying it didn't happen etc, just that if they couldn't prove it or there were no pockets for them to dip into there is little reason to pursue it from their standpoint and really yours.