What is the best way to have multiple profiles?

would you create logins for every user or would you use the same login on the Lexus app for every user?

since we currently only have one key how would the car recognize the user ? Via Bluetooth phone?

 

You could do it the old-fashioned standard way: one user profile and three separate seat memory settings.
For multiple profiles each user has to create their own Lexus login. Then each phone is associated with the specific profile, and when the car recognizes the phone it will load the profile. You'll also be able to switch profiles on the setting screen, if it did not load automatically.