It's not just spectrum, but lack of infrastructure as well, my nearst 5G cell is to far away it barely registers, on good day lucky if it goes up to 1 or 2 for a moment, then back to 0.
All cells where I am in SE London are either to far or behind buildings/hills, so we could do with closer one's for good 4G and to get 5G, Vodaphone here is useless, EE or O2 about okay but not great :o/
Infrastructure just poorly invested in London unless your in inner London for city folk, but us outer London folk are sod out of luck, broadband here is shit and pot porruri too :o(