Luther: The Fallen Sun (2023) review

Detective Chief Inspector John Luther (Idris Elba) - who's a hot-head that breaks protocol when he sees fit - is locked up for past offenses, gets some old friends to help spring him and then sets out to catch blackmailing serial killer David Robey (Andy Serkis), who runs a "red room" where he captures people and has viewers on the Internet decide how they'll be dispatched.  I confess to having never seen an episode of the popular BBC show, so I'm not sure if this is a proper continuation of the story or not - showrunner Neil Cross wrote the screenplay, so I'm going to assume it's faithful - but it just seems to me to be a standard (albeit techno-savvy) police procedural that is loaded with plot-holes and strange moves that don't always make sense, but Elba's presence helps carry it along to its arctic conclusion.  Fans of the program seem to be in the mixed-to-indifferent range, but I'd like to point out that Serkis' character can apparently speak ... Estonian?  Is there anything that guy can't do?