All youtube channels have their own feeds, but they're not obvious to find. The first part of the URL looks like this:
https://www.youtube.com/feeds/videos.xml?channel_id=
Go to the channel's home page and search the page source for "channel_id=" (with a long string of numbers and letters after it, often starting with a "U") then paste the ID after the equal sign. The channel id looks something like this: UCtwKon9qMt5YLVgQt1tvJKg
Yeah, this doesn't include community posts. I haven't tried finding one tho