Seems like a good question, I don't know why you are downvoted

There are tons and tons of lists on Letterboxd, a social network built around movies. Sounds like exactly what you're looking for. You can find popular lists, lists created by users that appeal to your tastes, official lists put out by the site, or anything else really.

EDIT: If you're looking for just a watch list, then images like this might be up your alley [Link to original tweet containing the image] [Nitter link]. The watch list is posted on Twitter or YouTube around the time the Four Play podcast finishes a film genre and announces their next one. (The image I linked is a watch list for film noir posted around the time they concluded a month of 1980s vampire films.)

If you're up for another recommendation, something that I've been enjoying that fits your request is the podcast, "Four Play," hosted on the Last Free Nation Culture YouTube Channel. Here's the premise of the podcast quoted from the video description of one of their most recent episodes:

Four Play selects four iconic films from a theme or genre to meticulously analyze and place in their proper historical context. Hosted by veteran esports commentators Richard Lewis, Duncan "Thorin" Shields, and Christopher "MonteCristo" Mykles, Four Play showcases both legendary Hollywood movies as well as hidden gems outside the mainstream.

What this description doesn't mention is that episodes drop once a week and the theme of the month, as well as a list of the four films selected, are announced in advance on their YouTube community page or Twitter page.

To address specific aspects of the Criterion Channel in your post that Four Play also provides:

put together a list of 6-12 movies

After they review the last of the four films of a selected theme, they recommend a list of films of that same theme that did not make the four, but are worth viewing if you're interested in that theme. For example, here's their list of cosmic horror films at the end of their review of From Beyond (1986) [timestamped Piped link] [timestamped YouTube link].

overview of the theme

Whenever they begin a theme or genre, they give an intro to the genre and the historical context. They provided an overview of cosmic horror in the inaugural episode of the podcast in which they discussed The Thing (1982) [timestamped Piped] [timestamped YouTube].

the curated list for a given theme gets me to branch out from what I may typically watch in that I know it’s generally going to be a good movie

For me, at least, I generally enjoyed the films that were introduced to me through this podcast. I think what they excel at is recommending these lesser known films that you might find are underrated bangers. In their month of cosmic horror, for example, they reviewed The Thing and Annihilation (2018), two well-known movies that have been in the cultural conversation, but also Event Horizon (1997) and From Beyond, two lesser known movies that are, if not severely underrated, worth watching at least once for the experience.