There is, well used to be when I was young, a way round paying high premiums for a decent car at a young age.
What you need is an understanding parent or someone very much older than you that can get a cheap policy on the Lexus. Then they register and insure the Lexus in their name and you buy, register and insure a low insurance group banger, something like one litre Corsa. Take out an insurance policy that enables you to drive other cars and you will be have third party only insurance to drive the Lexus. Fully legal and above board.
Now, that's how we done it quite a few years ago so the insurers may have moved the goalposts but it's worth looking into.