I am not at all surprised that a rebuilding year would result in a poorer finish than the previous year. It is exactly that, a rebuilding year, with new players, new manager, etc.. The fruit of the rebuilding should come in the future, and the fandom should be prepared not to make the playoffs because, hey, its a rebuilding year. Unless in your opinion 2020 was absolute rock bottom for the club.
A) 2020 should have been the rock bottom
B) I don't believe there needs to be anything called a "rebuilding year" in MLS. It's not like other sports where you are very limited in how much you can do from one year to the next, heavily dependent on draft picks and trade opportunities. We are just one or two players away from being a contender, and there is no reason we couldn't have gone out and gotten those one or two players in the summer window. Maybe we are cap-constrained with all the money wasted on the bench and down on RB2, but 100% could have done more to contend this year, and we simply chose not to.