Kudos for trying to “steelman” their argument rather than strawman it.

As devil’s advocate, we have no long term data about the vaccine, and people with it are still getting COVID, and may need another booster for variants. Is their prolonged and survived exposure to COVID really less effective than introducing the vaccine into their system? The risk profiles are different, but is the vaccine more effective than the antibodies they already have produced naturally? I don’t know answer, just curious rambling.

Where is the logical flaw? I think this argument would be pretty reasonable if the potential risks of the vaccine were orders of magnitude greater.

The GLARING logical flaw is that vaccines are safe and effective.

But they're not 100% safe, and if the guards already have immunity, then they're not effective.

In fact, I may be reading too much into your dropping of the article on "vaccines" but there is a huge flaw in your logic. General facts about "vaccines" don't say something about a particular vaccine, especially a new one. But my apologies if you meant to write "these vaccines."

That's not a logical flaw; the logic is just based on an incorrect axiom.