To piece those two phrases together as one done, one would have to believe that: "Teaching them to observe all things whatsoever I have commanded you" is identical to "there are also many other things which Jesus did"....I can't see how you can maintain any intellectual honesty and say those two subjects are interchangeable.
I hate to tell you, but when one commands someone to do something it is an act (as in He did something...He commanded). The act of commanding is something that “person” did. One of the things Jesus did was command the Apostles to “baptize in the name...etc.” John tells us He did many more things. By extension some of those “dids” would include other things He commanded.
Again, unless you wish to put limits on what God can do with His “dids”.
Who claimed they were identical or interchangeable?
“Fit together perfectly” does not mean they are redundant, but rather more like complementary.