While Firefox doesn't surface them anymore, I checked the page source and there are indeed per-channel feeds. They don't have direct video URLs, but yt-dlp claims to support Nebula, so you may be able to automate it.

They have rss feeds[0] but it looks like it's more for notifications of new content or creators rather than direct downloads for the videos/podcasts. I don't think they'd implement something like direct downloads but idk.

ETA: Accessing content on nebula, I have my feed of videos from the creators to which I subscribe and I select videos to watch from there. It's basic but as someone who never got into watching youtube (I bookmarked channels on invidious instances and looked for new videos there) it's pretty good. They're also open to feature requests and are improving the site.

[0] https://blog.nebula.tv/rss-feed/