In that context, intent and motive matters. If a deed brings internal satisfaction (e.g. feeling good, relief, moral gratification, avoiding guilt, avoiding feeling like a monster) then it has a personal benefit, which negates true selflessness.

Doing good aligns with your values. That alignment feels good. It's not entirely selfless. There’s still a psychological incentive. That's still a form of gain. Even the burdened altruist gets something. If not peace, then at least the ability to function without drowning in self-loathing.

And if we start changing the definition of "selflessness" then it renders the entire argument moot.

Check. Your move.