2001-2021 was a terrible time for EPCOT.
In terms of additions you have Ratatouille, which in itself was the first actual park expansion in over 30 years. Mission: Space and Soarin' replaced existing attractions, and Frozen and Nemo were rethemes of existing attractions. Test Track received a significant update, I'll give you that, but I am hesitant to say Imagination and Mexico's were. Both of those updates were applying a band-aid in the form of characters onto an otherwise minimally changed attraction. In this same amount of time we also lost the entirety of Wonders of Life and Innoventions, both receiving no replacements.
Between park opening and 2001 EPCOT received a multitude of significant updates which blow what was done in the next 20 years entirely out of the water. This park has been heavily neglected, which is why they started doing significant work in the first place.