In some ways yes. Humanity has largely left natural selection behind.

How do we define "huge catastrophe"? Something like COVID probably applies and that was probably a wake up call to our fragility. Thankfully vaccines and social measures muted the worst of it, but we still a massive die-off of the old, immune compromised, and genetically unlucky.

I would argue it's less humans we should be worried about and rather things like our crops. If you research monocultures you'll get my point. Humans still have a tremendous amount of genetic diversity, it's unlikely a single plague lets say will wipe us out 100%. But most our major crops are essentially clones of each other. If there arises a COVID for wheat, then yes, if it kills one plant it can potentially eradicate wheat from existence. Look up the Gros Michele banana for information there. That should be a major concern for the future of humanity and something we strive to improve upon.