Something that could work really well here could be having a norm of using
the checksum for bright colors, weights, sizes, capitalizations, and/or
spacing of the characters of the address, making different addresses more
clearly visually distinct.

Ethereum uses mixed case to do this a little bit:
https://eips.ethereum.org/EIPS/eip-55#implementation

It seems to me the checksum at the end of the address is sufficient for
differentiating error, but making a checksum more visually distinctive is
indeed an opportunity to add another digest, reducing collisions and such.