We too are having huge issues with profiles. What is a brilliant car mechanically is spoiled with so much key functionality tied up in a profile system that plain does not work and worse is described by a handbook set that could best be described as very poorly and incompletely written.
The big problems we have are
Second profile = no smart functions
Adding a second profile requires linking to a second Lexus Link account and as soon as we do that the prime account loses 'ownership' and all access to smart functions (eg remote preset of temperature, lock/unlock etc). Unlink that second account and the second profile deletes itself from the car in seconds. No second profile means second driver really can't enjoy the car.
Prime profile doesn't reliably load
If we both get in the car than it's a 50:50 chance whether it will load the prime driver profile or Guest (=no recall of preferences, locations etc). Might be tolerable if the car offered the single key press select of correct profile (as page 59 of the multimedia handbook promises) but guess what, it doesn't.
There has to be a way. On the equivalent USA forum, user Kusala says he has the profiles working but here in the UK none of the dealer, the Tech Helpline or the handbook knows how.