https://www.phonearena.com/news/android-phones-lose-more-value-each-year-than-ios-handsets_id129618
Over one year, the average depreciation of an iPhone was 16.70% and 35.47% over two years.
Compare that to the average drop in value of 33.62% for an Android phone over one year and 61.50% over two.
After four years, the average iPhone has seen 66.43% of its value melt away compared to 81.11% for the average Android phone over the same time period.