Samsung s24 series promise 7 years of OS and security updates just the same as pixel 8 smartphones. Fairphone also promises up to 8 years of security updates and at least 5 os updates until 2031.
Samsung uses a mix of snapdragon and exynos. Fairphone uses an usual but enterprise grade midrange snapdragon processor. So, 7 years of updates do happen with snapdragon. Just depends on the manufacturer and the contract they have with Qualcomm.