update jellyfin

docker stop jellyfin
docker rm jellyfin
docker pull jellyfin/jellyfin:latest
docker run -d --name jellyfin --user 1000:1000 --group-add="132" --net=host --volume jellyfin-config:/config --volume jellyfin-cache:/cache --mount type=bind,source=/media/datapubl,target=/media,readonly --mount type=bind,source=/media/datapriv,target=/media1,readonly --restart=unless-stopped --device /dev/dri/renderD128:/dev/dri/renderD128  jellyfin/jellyfin

customize jellyfin

enter the docker

docker exec -u root -t -i docker_id /bin/bash

install tools

apt install mcedit wget

go to webroot

cd /jellyfin/jellyfin-web

get logo to webroot

wget https://www.leboeuf.eu/pics/leboeufplay.webp

change site title

sed -i 's/document.title="Jellyfin"/document.title="LeboeufVideo"/' "/jellyfin/jellyfin-web/main.jellyfin.bundle.js" && sed -i 's/document.title=e||"Jellyfin"}/document.title=e||"LeboeufVideo"}/' "/jellyfin/jellyfin-web/main.jellyfin.bundle.js" && sed -i 's/<title>Jellyfin/<title>LeboeufVideo/' "/jellyfin/jellyfin-web/index.html"

add logo on main page

mcedit session-login-index-html.c73c6453a153f384f752.chunk.js

find the following string:
<div class="padded-left padded-right padded-bottom-page margin-auto-y">

directly after this string paste the following (but obviously amend for your own logo, it can even be a GIF if you want): 
<img src="leboeufplay.webp" width=350px style="padding: 0px;display:block; margin-left: auto; margin-right: auto;">