First, since you did not accept the severance agreement you can still file a claim for discrimination. If the arbitration agreement is enforceable, then you may have to pursue the claim in arbitration rather than in court.

Second, the Coronavirus may help the employer defend against your claims, especially if others were laid off at the same time.

Third, you should consult with a lawyer about the facts and timing of your potential discrimination claims as well as the enforceability of the arbitration agreement.
Most provide free consultations.

Yes you can proceed to bring a legal action against your employer as long as you did not sign the severance agreement and as long as you can prove unlawful discrimination based on race or disability.

Whether you have to proceed in arbitration or in court will depend on whether the arbitration provision you signed is enforceable.

Whether you have a meritorious claim for discrimination or harassment will, of course, depend on the facts of your situation. However some of the claims be legally stale if this has been going on for years. There are some strict deadlines for bringing such claims. Therefore it would be wise for you to move quickly at this point.

Locate and consult with an experienced employment law attorney as soon as possible to explore your facts and determine your options. I would suggest you look either on this site in the Find a Lawyer section, or go to www.cela.org, the home page for the California Employment Lawyers Association, an organization whose members are dedicated to the representation of employees against their employers.

Most employment attorneys who practice this area of law offer a free or low cost consultation in the beginning and then, if the matter has merit and value, will usually agree to work on a contingency basis, meaning you can hire an attorney without paying any money until the matter results in a positive outcome for you. Many advance all the costs of the litigation as well. Do not let fear of fees and costs keep you from finding a good attorney.

Good luck to you.

If you have not signed the severance agreement, you can sue. However, if there is a valid arbitration agreement, it would likely be moved to arbitration. That isn't necessarily a bad thing. It's just different.

With respect to the discrimination, whether or not the employer fired you for good cause or not, discrimination is unacceptable. You may have a claim independent of the termination. If they are using the Coronavirus as a cover for discrimination, that could certainly be actionable.

You need to hire an attorney to go through these facts and give an opinion as to whether you should can or should go forward with litigation.