He doesn't even dress that bad. His dress is a subtle form of propaganda.
His country is at war and under siege. His manner of dressing is simple and military coded, to differentiate it from Putin, who wears a suit (businessman, KGB, etc). It subconsciously signals to his people (and soldiers) that he is in the fight with them even if he is a politician and leader far from the front lines. It also means that he can do things like quick exfils should the need arise, put on body armor, etc and still look somewhat put together.
Even given the nature of his dress, it looks better than Trump's bizarrely tailored suits.