Yeah, installing a new OS on a phone isn't something you do easily like on a PC.
You have to unlock the bootloader, which requires an unlock code from the manufacturer, then you have to factory reset it, and that's even if your phone/carrier allows it. Many don't (which is why it's so hard for me to replace my phone...grrr).
So yeah, installing a new OS on your phone is typically going to require quite a bit of effort and some level of commitment as well as a device that's bootloader unlockable and supported by an alternate OS (each device and model requires a custom build).
It's....a whole thing. It really shouldn't be, but it is :(