Yes white beetroot and white beets are OK to eat and they are edible and safe.
Sometimes the beets or beetroots will turn white inside and that is normal and nothing to worry about and the white beetroot or white beets are not an indication of bad beets or bad beetroot.
The taste may be a bit different but white beets and white beetroots are entirely safe to eat and you won't get sick or have any health issues when eating white beetroot or white beets.
Some beets can be white inside while being red outside and that is normal and the beet is still good and safe to eat.
Some beets grow to have a white inside while the outside is red or even sometimes other colors.
But the white beet is okay to eat when it's white inside.
Having a red beet that has a white inside is still a good beet and that is just how some beets grow.
Sometimes the red beets turn white inside because the soil was allowed to get too dry and the weather was too hot.
The white insides of a beet or beets are not an indication of bad beets but it usually means that they may not have gotten enough water.