Recruiting agency? Ask them to find you content job. Not SEO managing. Those, not content, tasks were not going well for you even before medical issue. If asked what happened, you were hired to do SEO management but realized that your talent is in content. They didn’t need content person long term though so you had to leave. You are now looking for content positions.

The issues with questioning arise possibly because you are looking for positions that you were let go from. That’s why they are questioning and rejecting. Usually if you were let go because you didn’t have skills they wanted, it’s problematic if you go look for the same type of job in similar type of companies unless you did something to improve your skills. Take a class? Have a record of you getting additional education.

Otherwise look for a different job. If content jobs aren’t there, what type of jobs could you go for? Is there something else?