I've been trying to download baritone for 1.19, but when I click on the versions, they all say "expired". Am I just not looking at the most updated versions of the 1.19 versions? Or can you not get them anymore?

you can get the 1.19.2 version here
or the 1.19.3 version here

In case those links expire as well (they will) you can find a list of all successful CI builds on the Baritone repository here (note that 1.19.2 is on the 1.19.1 branch) and until the 1.19.3 pr is merged you can find a list of its CI runs here.