First, we have Lestat and Marius's meeting. In the show, he drags Lestat out of the dirt like an animal, shakes him around, drags him back to his "shrine" (we'll get to that) and largely leaves him to come-to on his own.

In the book, Lestat is the one seeking Marius out. As Lestat is "dirt napping," here's how Marius's approach is described:

"...like a beam of light." Where is that sentiment in the dimly-lit show? Where is the air of rescue, of salvation?

When Marius awakens Lestat, he does so with care, and it rejuvenates him:

Lestat describes Marius as "the purest image of human love:"

Show!Marius is distant, detached from Lestat. He drips blood from his wrist into Lestat's mouth, while in the book, he holds him close, offers him blood from the intimate source of his own neck:

Marius's heart swells for Lestat:

All of this love and care is absent in the show's abysmal display. This is Lestat's true perspective, words from his own mouth, in his own book. The show gives us none of that.

In the book, when Marius takes Lestat back to the shrine, they pass by mortals who Marius lives amongst, who revere him:

While in the show, Marius is shown to be isolated, rarely in contact with the outside, mortal world he so very much loves, even a little disparaging of it:

One of Marius's main traits is that he is one of the vampires most connected to and appreciative of humanity. Again, something the show stripped from him in the very short time he's shown.

In the book, he leaves Lestat in a room with his own belongings, including Nicki's violin which he saves for him:

Here, it's also made clear that Marius takes care of his guests, as he leaves Lestat to rest in a well-protected room that Lestat describes as such:

Contrast to the show, where Lestat awakens alone, exposed, having to find his own way through this unknown place to find the stranger to him that is Marius.

Book!Marius's abode is full of books and furniture, and he sits with Lestat to tell him his history:

Marius and his home serve to reconnect Lestat to the humanity he feels so distant from:

Marius is actually concerned that Lestat may feel afraid of him:

And he's eloquent! Polite!:

Show!Marius is a total kook who isn't all there in the head, where, again, a large part of Marius's actual character is how grounded he is, how Lestat leans on him to guide him through his current depression. He's a loving, paternal figure:

Then, Show!Marius's "shrine" for the Mother and the Father is messy, unkept, dark, and depressing.

Akasha & Enkil lay on slabs in the middle of this dreary, cavernous room devoid of color, while in the books, Marius arranges them respectfully, decorates for them:

Compare this to:

whatever this is, lol.

In the book, Marius takes great care of them (it's kind of his Whole Thing), especially the shrine in which they are kept:

Do you see any of this reverent beauty in what the show gives us? If you do, you're watching something else entirely, or have Rolin Jones They Live glasses on. We aren't shown a shrine, we're shown a crypt.

We haven't even gotten to the worst of it, which is how the show makes Marius (of all people! of all vampires!) seemingly so irresponsible that Enkil is destroyed after a night of drunkenness: "Two bottles of ginger flower gin in the veins of a celebratory meal. ... [I] Left him above in the sun."

This is unfathomable for the real Marius, whose purpose is to take care of the Mother and the Father, who takes the mantle up himself specifically from those who deliberately put them into the sun in an effort to destroy all of vampirekind. Sure, I'll give you that Enkil's destruction in the show is suspicious, but what we've been presented thus far has been such a total betrayal of his true character that it's not unreasonable to take this at face value for the time being, especially when we're not shown anything to the contrary. We're not given any reason to doubt Lestat's descriptions. Keep in mind, Lestat's own recollection of Claudia's turning in season 2 was the most accurate depiction of the event. Why are we suddenly meant to assume these are any different?

Furthermore, Show!Marius gives an air of not respecting the autonomy of Akasha (and by extension Enkil). He is not like this in the books, he knows their power, and when they move he returns them to their places out of respect and in awe of their powers, to keep them protected from those who wish to destroy them:

He speaks (telepathically) to them with respect:

All things he does not do in the show, where he keeps them confined to this cobblestone hell, locked within themselves, forbidding Akasha to be enriched. In the books, Akasha and Enkil refuse to and rarely drink blood, whereas in the show Marius has an active hand in preventing them from being nourished.

Book!Marius does not want to pass on the job of caretaker to Lestat at all. He is jealous of Akasha and Lestat sharing the blood, yes, but he does not ever once "lose himself" the way the show insists he has. Marius represents an ancient who has so far been able to keep himself grounded, albeit attached to his responsibility. That's partially why Lestat seeks him out in the first place, to get answers.

In previous seasons, we are shown characters through the eyes of Louis, yet these depictions nonetheless remain consistent and reasonably accurate to their book counterparts. Why is Lestat any different, especially when his own book from his own POV contains none of these "biased" elements, and as I said before the audience has been told to rely on his perspective, such as in the case of Claudia's turning?