I'm not sure it's "official" but if I remember correctly they do one stream (the Developer Roundtable) for Champions and above the last Thursday of the Month and then release that video publicly a week later on the next Friday. They also do a different stream the first Thursday of the month. This usually means that for someone who isn't Champion and above will receive two streams during the first week of the month. It also means we have a while to wait until the next stream.
I'm actually hoping a letter comes out soon from Ben Dean. Joppa mentioned the patch notes would be included in the next letter and it's been a couple of months since the last letter.
I hear you on that Pantheon itch though. I just rewatched the June 3rd stream again. I would suggest combing through some of the older streams too if you haven't already. There's a ton of content out there and several gameplay videos, just realize that some information/footage is fairly outdated.
https://seforums.pantheonmmo.com/content/forums/topic/9329/stream-links-all-in-one-post