Parenting adults

I need help in dealing with my oldest (26) and youngest child (14). They both have similar tendencies such as difficulty with emotional regulation, low frustration tolerance, always seeing the negative side of things, and they can be impulsive and risk taking.
The older one moved to another country by herself since when she was 18. She has a very strong need to feel independent and in control of herself. I feel anxious if she doesnt abide by common sense safety rules when she comes home to visit (i dont know what she does when she is away and I know I cant control that). For example- She will scoot home from the gym alone in the middle of the night or go in a car with a strange man she just met at the gym. I ask her to be considerate and not go out alone when shes here but she said she will not come to visit if I make her abide by these rules. I know she is grown up but I get alot of anxiety from knowing that she is walking alone at night and feel she should be considerate and not make me worry when shes home. I also feel like I need to walk on eggshells when talking to her. If I say anything she doesnt like, she will hang up on me or block me, for days or weeks at a time. I only have her best interest in mind and good intentions when talking to her or giving advice but she cant see it that way.

I see the relationship with my son who is 14 going on a similar path..I also have to walk on eggshells when talking to him to prevent an intense reaction and he also hangs up on me all the time and has blocked me. He is also a risk taker (he just broke both his wrists by falling off his bike) and I worry about giving him the independence he craves like his sister. I have kids in the middle who are more cautious and I dont worry about them nearly as much.

Please tell me how I can deal with these behaviors in an adult child and in my teen?