You're not forced if you use a more open ROM of Android, like LineageOS. You can even keep using Google apps. Many phone models will keep getting updates on custom ROMs years after their stock image does.
Installing LineageOS involves unlocking the bootloader and/or acquiring root, which will make several applications (mostly banking, but afaik some streaming apps as well) refuse to launch, because your phone now trips SafetyNet (which is "yet another thing I don't need, but have to pay for").