Jellyfin-web is part of the container. You don't need to provide anything in the docker compose for Jellyfin-web, unless you are trying to pass in custom files or something.
Jellyfin 10.10.6 (Docker)
Ubuntu 24.04 LTS
Intel i3 12100
Intel Arc A380
OS drive - SK Hynix P41 1TB
Storage
3x WD Red Pro 6TB CMR in RAIDZ1 (JF Library)