I came across this task in the process of scheduling https://gerrit.wikimedia.org/r/c/operations/puppet/+/1238369 for a puppet request window (and seeing if Tool-schedule-deployment would be able to do it for me).
It seems like this feature might be nice to have, at least for puppet requests (I can't personally speak to infra windows) :)

This would be a lot less painful to implement if something like T366880: Consider using JSON content model for deployment calendar were done first. The business logic used by Tool-schedule-deployment to parse wikitext into structured data is horrible. Like seriously horrible. I committed these crimes against python because way too many people were spending way too much time editing the Deployments page for backports. I totally agree that it would be nice to generalize things so that other types of assisted deployments were easier to manage too. I just don't want to be on the hook for fixing the myriad ways that can be broken compounding the existing problems of the current use case.

Fair, fair :) (To be clear, my comment should just be taken as a general +1 towards the idea, rather than trying to obligate anyone to work on it right now, esp. given what you've said!)

jiji opened https://gitlab.wikimedia.org/toolforge-repos/schedule-deployment/-/merge_requests/23

Support MediaWiki infrastructure scheduling