That's easy, you only have to invent a time-machine first. You weren't actually "out of work" if you instead did extensive charity work.

I'm in a similar position as OP: 2-year gap due to burnout and deep depression. I couldn't do anything beyond not killing myself, I was unable to get anything new into my brain, I touched no projects, I had burned all bridges and basically all my technical and social skills atrophied during the pandemic.

I'm no liar though, I wouldn't dare to pad my CV with stuff which I haven't actually done. I wouldn't even lie in an interview, only that I don't get any interviews at all, which I assume is because of the obvious red flag of the employment gap.

Only my savings kept my afloat until today.