The only realistic place we can go from here is MC either just kills himself (if he even can) or is the god's slave and does exactly what he wants for the rest of his miserable existence because he can't hope to match his power and has no other outs, and either way all of his friends are dead and have been erased from existence entirely. As a result, this can no longer go anywhere interesting, because the author will either remain consistent and tell an incredibly depressing story where the MC is a powerless cuck, or will pull something out of his ass to make the MC powerful enough to kill the god, which will make him totally unbeatable and omnipotently powerful until the next big bad is somehow even more powerful in an endless cycle of asspulls and power creep.