It won't necessarily be easy to set up, but I assure you that the updates over the year are more than a factor of ten smaller compared to the initial download of TeX Live in week 0, which is precisely why it's crucial to deduplicate in week 0 by layering the schemes but not necessarily in the following weeks. It's easy to demonstrate that by downloading a TL 2021 ISO and then updating it.
Yeah, we would probably need a separate Dockerfile for the week 0 seed image.
And there are other concerns, too. It's not ideal to use a year-old base image, so perhaps we want to at least apply security updates once every N weeks.
Hi, I've submitted TeX-Live/texdoc#79 to have it redirect to texdoc.org if the user has no documentation locally installed. This is a fairy popular program, so I just want to make sure that you think that the server can handle the load.