When using VisualEditor (included with MediaWiki 1.35), I ran into this issue: https://www.mediawiki.org/wiki/Topic:Vevdw6kw6itlr0x7 (Pages with slashes (/) in title result in 404 error)
I managed to fix this by going into the Docker container and adding the following line to the VirtualHost block in /etc/apache2/sites-enabled/000-default.conf (as suggested in the topic):
AllowEncodedSlashes NoDecode