With this handset, does repairable == right to repair the operating system == supported jailbreaking?

I recently went though some frustration to root a Samsung handset - it required sorting through endless blog posts linking random executables from megaupload or google drive. Fragmented instructions on various forums; many incomplete or incorrect.

Which Android handsets best support rooting/jailbreaking by the vendor which provides a supported way to both unlock the bootloader and provide root access?