That would be Brandon Hendrickson, who won the title in 2018 and 2020. Men’s Physique has been at the Olympia since 2013. Here’s a list of every champion, from the Olympia’s website:
2013: Mark Anthony Wingson
2014-2017: Jeremy Buendia
2018: Brandon Hendrickson
2019: Raymont Edmonds
2020: Brandon Hendrickson