If Disney can save a buck by writing out a character in the next season / movie, they will and imo doesn't not infer anything such as inferring a season 4. They could just reference that she decided to try and start another mandlorian colony or anything else that may explain her absence.
Amazon did the same thing with Cary-Hiroyuki Tagawa Nobusuke Tagomi in the man in the high castle. He just isn't there in season 4 but was a pretty important / main character in seasons 1 -3. The explanation was he was assassinated in the opening episode, but it didn't even show his face or anything else. Granted the actor had a scheduling conflict which is the reason, but just shows producers can pretty much write anybody out of a series with a short blurb or scene.
