Trademark Dispute — employer claiming my side project IP

Has anyone dealt with something like this? I'm not sure what my options are.

employer claiming my side project IP. I've been dealing with this for about 14 weeks now and the situation isn't improving.

This involves content I created over the past 14 months. I do have documentation proving my ownership and timeline.

Do I have a strong case? What should my next steps be?

Ok so oh god, another one of these.

What worked for me was filing with the appropriate government agency. It took 4-8 months but was worth it fr fr.