From https://graphviz.org/docs/outputs/ascii/

Since Graphviz 13.0.0, if Graphviz was built with AAlib support, the output format ascii will produce an ASCII art representation of the input graph.

Simply set the output format to ascii:

dot -Tascii input.dot

Note: as of writing (April 2025), version 13.0.0 is unreleased - https://gitlab.com/graphviz/graphviz/-/blob/dcdd75784dbe655b728da4d62a3b1e4aed142521/CHANGELOG.md