I actually watch Shawn Willsey's content for everything but this topic. I find his Grindavik coverage isn't that great. It's overlong, over-speculative, and sometimes missed more current or extended information available elsewhere. Some of this I think is due to his being a relatively newer YouTuber (in terms of gaining traction) and his personal interest in Iceland: to be clear, its not that he's disingenuous or unqualified... its more that he's not yet crafted a public presentation style which fits the medium better. However his roadcut geology series is interesting even if you're only getting his on the spot opinions of what he's observing.

By far, the best source about what's going on in Grindavik I've found is just the Icelandic Meteorological Office website: https://en.vedur.is/ (English version, which is quite good). That in combination with some residents of Iceland that post shorter updates the keeps close to the reported local news seems to be the best.