I think it's fair to surmise, that Boeing has lost all creditability when it comes to projecting a return to service timeline for the Max.
Ever since the grounding they've peddled the same message every 3 months: In 3 months we'll get the approval and the grounding will be lifted. Well, it hasn't happened yet and to my knowledge neither the FAA, nor EASA or CAAC, have committed to anything or provided guidance as to when RTS may be expected. To exacerbate the situation, as long as there's Covid-19 lockdowns, closed borders and travel bans in place there's simply no way the necessary tasks can be accomplished.