Honestly, with how powerful modern Smartphones are, you can just buy one now, flash an open source version of android and use that for a decade, assuming the OS gets supported that long.
Get a device that is supported by degoogled android systems and get rid of all the garbage. My recommendation is always GrapheneOS on a pixel, just because you can reinstall google play services if you really need to and preserve usability, while massively boosting privacy and security.
Windows kind of has that too, with all the .MSI, .exe, .msix and all the appxpackages and how almost none of that works out of the box anymore because you’d otherwise be able to install another browser without opening edge once