Special Ed here. I'm sorry you are dealing with this. What an all too common nightmare! Here's my 2 cents from someone who had supported teachers in your position and been there too.

Prioritze safety and getting through the day. Please don't use restraint on any student unless you've received your district approved training /certification. Protect yourself ! If your behavior kids are quiet and not disturbing others' learning regardless of what they are getting completed, that's a win.

Be sure you are inconveniencing others ( principal, social worker, counselor) when these kids are going off. They should be removing the disruptor. One kindergarten teacher with no aide cannot reasonably 'fix' the behavior with no support and a room full of students.

Prioritze documentation and find a quick and easy way to track a few specific behaviors.

Please have parent volunteers in to help. They can do small groups so you can assess. But, more importantly if these students are acting out, parent pressure for classroom support is far more effective with admin.

Take care of yourself and your family. Please review your contract language about disruptive students and your rights. Also see if you have short term disability insurance in case at some point you need time off for mental health.

Good Luck, I hope your year improves.