The Fairphone is faster - although perhaps not by a huge amount, has better battery life and a better camera. The official spare parts shop has parts for the Fairphone 3 onwards, earlier models’ parts are sold out. The Fairphone 2 was released in 2015 and has stopped receiving software updates this year, the 3 came out in 2019. 8 years of support and replacement parts seems to me to be much better than what Samsung or Google would offer you.
Specs differences: https://www.gsmarena.com/compare.php3?&idPhone1=12540&idPhone2=9536#diff-*,*,*
Chipset comparison: https://versus.com/en/qualcomm-qcm6490-vs-samsung-exynos-9820
Spare parts shop: https://shop.fairphone.com/shop/category/spare-parts-4?ref=header
As someone who works on embedded devices: HDDs are used for media storage and can be easily replaced. Any NAND as a limited life span and good embedded software will try very hard to minimise writes. Though in my particular area, there’s additional security constraints on the OS, which preclude any removable flash storage from being used.