Tennis is indeed big in UK (together with some other sports including track cycling) and we can only imagine what it would give if Radanescu would be able to win Wimbledon. Last British female winner dates already back from 1977.
It was certainly a big deal when Andy Murray won his first slam (also US Open), and then an even bigger deal when he won Wimbledon the following year. There will be a huge amount of expectation on Raducanu next Wimbledon, but given how she coped with the pressures of the US Open I think she'll be fine. But I think not just the fact of her US Open win, but also - and mainly - the nature of it, will already be a huge catalyst for the women's game here.