It's a weird idea all around. I really only know Robbie for three songs ("Millennium", "Angels" and "Rock DJ"). I remember being creeped out by the Rock DJ video as a kid. But, making it a Monkey Man is weird and tanks any appeal of a crossover hit. Also, it's not even doing that well in the UK as they find Robbie mostly annoying.
That said, it's getting good reviews, and I've seen people online say it's the best biopic since Rocketman. I might check it out despite not knowing much about Robbie Williams. I know this movie has been memed to death online, but I can't really mock it for trying something new with the stale biopic formula. Same with that weird Lego Pharell Williams biopic.