Of note:
"One of the notable issues is that this process also won’t delete all of your data — according to 23andMe’s privacy disclosure, your genetic information, date of birth, and sex will be retained for an undisclosed amount of time to comply with the company’s legal obligations, alongside “limited information related to your account,” such as your email address and communications around your data deletion request.
23andMe did not answer our questions regarding what specific data actually is retained or deleted when a user removes their account. Some posts have appeared online that encourage 23andMe users to scramble their data before deletion by replacing things like name, date of birth, ethnicity, sex marker, and height with false equivalents. This will supposedly render any information that is retained useless, but will likely be ineffective if 23andMe only stores the data that was used to create your account — something that the company also did not clarify to The Verge."
It also has no impact on research studies you're already part of, all it does is prevent your DNA from being added to new studies.