If I wanted to modernize IRC today, I would focus on Matrix.
Thanks for the link to matrix.org though.
Quoting from https://modern.ircdocs.horse/
This document intends to be a useful overview and reference of the IRC client protocol as it is implemented today.matrix/riot is indeed a good attempt but if you are going to modernize it, it makes sense to use a modern stack to keep up with the times.
[1] https://github.com/matrix-org/dendrite
[2] https://github.com/ruma/ruma
[3] https://github.com/bismark/matrex
[4] https://matrix.org/docs/projects/try-matrix-now.html#servers