I don’t think that Photon emissions from an atom are coming from inside the atom. There’s only so much space inside of an atom, it can only store so many photons. So, what if the photons are not coming from inside the atom, but they’re coming from dark matter. The atom pulls dark matter in, processes it and releases photons as a by-product?
Dark matter could be like a type of fuel for the atom, and then it releases photons. That’s why the atomic decay is able to keep going virtually forever.