Is it really that difficult to rent a house in the UK? What do you need to watch out for?

Planning to study in the UK next year. Heard a lot about the housing struggle—people say it's tough, need to book like six months in advance. What should I watch out for if I'm booking this early? Oh wise XiaoHongShu community, seeking recommendations and insights! The cities on my list are London, Birmingham, and Edinburgh. 🇬🇧