Ditch Arbitio. It's expensive and discombobulating. Do LNAT practice tests instead. Read a lot of news and current affairs.
There is no hit or miss LNAT score for Oxford. In 2023-24, Oxford made offers to people with LNAT scores as low (IIRC) as 16 and rejected without interview an applicant who scored 37. IIRC, the average LNAT score among offer recipients was 27.
I do not know what approach LSE etc take to the LNAT, but others here may know that.