Looking at the age of your Lexus (your profile says 2021), I would guess that was when you traded in your Audi to buy it. That was at a time when Covid has caused massive supply problems for all brands, and new and used car prices were increasing rapidly. I think the £3000 loss on your Audi over three years is something to celebrate, but it was caused by exceptional circumstances, and is not a benchmark to be used for measuring depreciation.