LineageOS is one of the most popular Android custom ROMs out there, and its roots don’t surprise. The lineage to which its name alludes is the now-dead CyanogenMod project and remains open-source. Among its benefits is to provide devices with manufacturers’ skins and longer-term software support a highly configurable stock of Android-like experience.
You need experience, of course, when flashing ROMs on an Android smartphone or watching a YouTube video on at least how to do so. You may brick your device, of course, so it’s probably better to install the ROM if you have an old phone that isn’t your everyday driver any longer. Also, as these are not included with the version LineageOS 18.1, you will need to install Google applications and the services individually.