When is trying to keep your parents safe is hurting your relationship.
Know when to push them to do what will keep them safe and when to bite your tongue.
I remember showing a family an apartment where I was the administrator of an elderly apartment building. The daughter said, "Now Mom you realize this is the curtain rod and you should not use it as a grab bar." The mother turned to me and rolled her eyes.
Have you recently been yelling at your parents for constantly going out when health departments are encouraging older adults to stay home? Does it seem like you are always at odds with each other, especially lately when they won't do what you know is right for them?
If your parent has dementia and is unable to make sound judgments, than you need to intervene when they are doing things that could cause harm to themselves or others. Taking away a car, unplugging the stove, or moving them into a memory care unit are issues that are non-negotiable. You may need to have them declared incompetent and becoming their guardian. You should however, still treat someone with dementia with respect and let them make decisions that are not going to effect their health or well being.
If they do not have a dementia diagnosis (forgetting some names does not count) you may need to change your approach. Your parents will think you are infantilizing them, and they may not be wrong. If you are constantly telling your parents what to do and chastising them for even simple decisions, you could permanently be hurting your relationship with them. They may go as far as to distance themselves from you.
"Why did you eat that?" "Why did you drive there at night?" If you want to express these thoughts try, "I am worried your diabetes will get out of control and you will need to go to the emergency room if you eat too many sweets. Can I buy you some sugar free candy?" "I can call Uber for you which will drive you there."
And what if the answer is still: I will do what I want! What are you supposed to do then? I believe you need to bite your tongue and say a prayer. You might say, "But they might hurt themselves." True, but they are also adults who are of sound mind. Instead, you need to tell them, without too much emotion, that you are concerned about them and love them but fear what they are doing will be harmful. Then you have said you piece and can do no more.
If you are constantly at odds with them, and this is fracturing your relationship, you will regret it when they pass away. You will need to ask yourself if arguing over a candy bar is worth a lifetime of guilt and regret.