I think Luke’s depiction and philosophy in the old Expanded Universe are much more consistent with Lucas’ two trilogies than Luke’s depiction in The Book of Boba Fett.
The rules of the Jedi Order of the Prequel Era are absolutely flawed, if not even terrible. Being totally selfless is impossible. Love always requires a certain degree of possessiveness. If I love someone, I want to be with that person not only because I like him/her as a person, but also because the presence of that person makes me happy and makes me feel good. If the presence of that person didn’t make me feel good, then there would be no reason for me to engage in a romantic relationship with that person in the first place. In love, you have to give and receive. You give your love in the hope that your love will be reciprocated and that the exchange of that love will make you happy. A stoic love without attachment is simply not true love, but a generic feeling of relative interest. Like it or not, attachment is an absolutely natural thing that is part of human psychology. We are all attached to someone. It’s not right to kill someone to save a person we love, but at the same time it’s absolutely right to worry about those we love and wish they are well. If we find out that someone we love is in danger of life, then it’s right to try to save him/her. Not just because we want that person to be good, but also because that person makes us feel good. In life one cannot be either entirely selfless or completely selfish. You need a balance, and that’s what neither the Jedi nor the Sith (as well as George Lucas himself) have ever understood. Being concerned and afraid for the people we love is absolutely natural, we just have to learn not to let these fears dominate us and cloud our judgment. Expressing all emotions, even negative ones, is absolutely right, and that’s what the Jedi should have taught. Not teaching that attachment is something that should be avoided at all cost, but understanding that it’s natural, understanding that the negative emotions that arise from it are absolutely natural, and therefore learning to control them and not letting them dominate one’s judgment, basing on the personal situation and personal needs of every single individual.
I’m sorry, but “Be happy for those who turn into the Force” is not a balanced and human teaching, not at all. On the contrary, “Protect the ones you love, do everything you can to make them feel good, but if in the end you don’t succeed, then, only then, you have to learn to let go”, this is a deep, human and healthy teaching. But what did the Jedi do instead? To avoid the Dark Side at all cost, they simply preferred to bypass the problem. Instead of studying and understanding the personal situation and needs of each individual, and instead of teaching how to express your attachment towards others in a balanced and controlled way, they acted in an extremist way by eliminating the possibility of having any attachment. Instead of teaching to have good relationships, they simply forbade having relationships in the first place, teaching to repress any negative feelings. And what has this led to? It led Anakin to be immersed between two opposite extremes: pure passion and pure stoicism. They taught him to repress every negative feeling, leaving him unprepared for tragedies. And guess what, when people are unprepared to deal with a tragedy then, when a tragedy happens to them, they offen react violently. No wonder Anakin went completely crazy and turned to the Dark Side. They didn’t teach him to deal with his negative feelings in a human and healthy way, they let him be manipulated by Palpatine who fed his negative feelings by gradually teaching him to deal with them in the wrong way, and as a result the Galaxy has been completely fucked up.
I think Luke’s philosophy in the old EU is much more consistent with the 6 original films precisely for this reason. Luke learned from the mistakes of the old Jedi Order and created a philosophy that doesn’t necessarily violate the old Code, but at the same time allows people to express themselves freely and deal with their negative emotions in the correct way. On the contrary, his philosophy in The Book of Boba Fett isn’t consistent with the films, because Luke proves that he has learned nothing from the mistakes of the old Jedi and conveys the message that what happened with Anakin was exclusively his fault, and not even fault of the dogmatic interpretation the Jedi of the Prequel Era had of the Code, a dogmatic interpretation that forbade absolutely normal feelings.
In addition, I think Lucas’ quotes regarding the whole “Luke shouldn’t marry” thing should be contextualized, because they’re quotes dating back to the time when Lucas had his first divorce. At the time he had strong anti-marriage feelings because of this, so we shouldn’t take those quotes as if they were his immutable thought.