Without further ado, straight to the facts: last version with sane amount of system services, which can’t be turned off absence of [neural networks API] , which is used for telemetry, collection/profiling user data with subsequent uploading collected information to third-parties [for the first time technology was introduced in Android 8.1] full support of any modern browser [even Android 6.0 can handle this] ability to load legacy Android 2.x applications without any issues [Android 14 is already blocking such apps] I care about older stuff simply because of code quality.
Stop using mainstream operating systems like Windows 11/10/8.1, modern Linux, like Ubuntu or modern MacOS versions. On mobile Android 14/13/12/11/10/9/8.1 are prohibited because they use neural networks to profile your device and dial back to “home” to dump your personal data and preferences. iOS from very beginning was very phony platform. My personal choices are Windows 7 for desktop and Android 8.0 for mobile. These two cover my digital needs fully, no restrictions whatsoever.