I have had a bad experience with a company that has since dismissed me

I am just shy of 2 years working with this company that dismissed me on grounds of "Capability", I'm going through to make a claim because of the injustice and hurt. I have suffered "ageism". I requested a DSAR on being dismissed just under 3 months ago and discoverd a concerted effort to get rid of me during the company process (Despite thefact that I was performing well). I'm in IT and have 35 years experience. Should I pursue the ageism or the "plot" to get me out the door? This is a law student question, so I hope this question is in the right area of the forum. Thankyou