Yes, there will be exactly three more in the club's history.
Graham Potter will join to a chorus of groans shortly after Ten Hag's strong six month spell under the new INEOS regime is cut short by a fall out with David Braillsford, the two gentlemen disagreeing strongly over their favourite brand of conditioner.
Potter will carry on Ten Hag's good start to the season by helping United to an incredible unbeaten run, stretching from January to June. He will, however be deemed lucky rather than good, with news outlets branding him as "The Emotionally Intelligent One" before realising that's a terrible name to fit into headlines. They will then churn out hit pieces in an attempt to sway fan opinion against him, with articles such as "5-0 Red Devils away win papers over Jonny Evans' crack" earning several billion reinstabooktweets to the embarrassment of United fans everywhere. A single tear will roll down Potter's cheek when his P45 and manager of the year award are handed to him on the same day.
It'll be Kieran McKenna's turn next aka 'The PE teacher's assistant.' He will lose his first three matches, leading to calls for him to be sacked and forced to give the club back every penny he'd been paid, along with his first born as apparently nobody would have shagged him if Ole hadn't given him a job all those years ago. But he'll turn it around by hiring Ole Gunnar in the role of 'Tactical Guru' which will be an appointment met with decidedly mixed reception by the fanbase. With United not wanting to face the embarrassment of having players claiming that they'd changed McKenna's nappies when he was a child, the club will be forced to focus their recruitment on youth and quickly kick any players approaching 30 (so basically anyone over 25) to the curb. It'll work, and Manchester United will have an enthusiastic young squad brimming with talent. A fantastic period of success will come to an end when McKenna's relationship with Ole (which was far more than a professional one) ends. "The magic is just ... gone," the Norwegian will tell Kieran one hazy morning. Weeks later, United fans up and down the country will say the same thing to each other.
Gareth Southgate will take over and the final seal will break, bringing forth Lillet from the void.