In fairness, most of those who fled were women, children and elders. Fighting age men are leaving now, that’s due to things becoming more clear on the ground. Russia has set up defense lines and says “come and get us”. Russia shuts down areas of Ukraine for hours by doing flyovers of dangerous bombers (Air superiority). Just harassment but as Q-Bait has noted it works. People can’t accomplish much when hiding in bunkers, it’s good mental warfare by the Russians.
My friends and business associates in Krakow tell me there's plenty of young men among the "refugees" they see everywhere. They complain that many drive nice cars and have bid up housing prices in their area. It would make sense that those with money and connections were the first to leave. They weren't fools - they knew from the beginning they would be drafted.
So NO, I do not believe for a second that millions of able-bodied men did not flee Ukraine in Feb. 2022.
Where did you dig up that bit of fiction?