Kamen Rider X (1974)

Both have our heros family being killed at the start of the show with them then being rebuilt into cyborgs wage a never ending battle against evil

Amazon is the series after X so if you want to watch the Kamen Rider seasons in order watch Amazon after X.

Cyborg protagonists fight against evil to protect the innocent. Both have a darker tone to start with but both lighten up as the shows go on