Ugh I don't plan to continue this because we'll never reach a conclusion at this point.
He regenerated after getting completely annihilated by Laplace explosion, to answer you question did his body ever regenerate?
But let's take the Eris' case.
During the fight, they cut off four of his arms (he used two to reinforce two others).
When Badigadi was annihilated by Eris, what remained from him and FGA, that's to say dust or atoms or whatever fell into the ravine, and Rudeus still wanted to seal him.
And after that they directly collected the arms to seal them, and once sealed they cannot regenerate/he cannot regenerate from them.
Currently, five parts of his body are sealed; that is, his main body, which fell into the ravine and started to regenerate at some point, and his four arms, which were severed. So, his main body regenerated from the dust, not his arms.