I noticed that you do install the whole TeXLive using apt-get and then remove the doc using the wildcard. Done so, Your
containers are ~2GB big. I'd recommend you to take a look at dedicated TeXLive installer available here. It is possible to create custom instalation profile and then
install directly without documentation by running
./install-tl --profile=<generated profile>. Using this approach
I reached the container size about 1.1GB with full TexLive 2019 installation.
I don't want to maintain my own container for LaTeX anymore and your's seems to be the best solution available on Docker Hub, so I'm suggesting you this little improvement.