You can do this by re-writing 90% of the character class in C++.
Other than that. No. You are stuck with the capsule, which is what all movement is based on in the rest of the character class.
you can always add a cube to the character, make it not render, and manually check collision…
What is still not possible and should be is to rotate the capsule so you can have horizontal characters, but it’s not like Epic listens to the billion and one forum topics about how having it locked to a predefined item is detrimental to development or GAF really…