No, of course not.

Eru knew Melkor’s intentions fully, remember, he’s omniscient, in his mind, history already happened, nothing Melkor did could go against his original design. This begs the question “Why did Eru decide to create Melkor if he knew what would happen from the beginning?” The God from the Bible has a similar issue so the question of an omniscient and All-Powerful being allowing bad stuff to happen in the world has been present way before Tolkien’s world came about.

Eru on the other hand has at least the benefit of the doubt in which he isn’t forcibly or continuously trying to force people to submit to him, for the most part he just lets the universe and it’s events unfold and rarely intervenes directly. The sinking of Númenor isn’t particularly a good showcase of Eru’s “loving” nature.

Does he love his children? Sure, but this does not mean that he’d prevent bad deeds and such to befall on them. Why does Eru allow Melkor’s corruption to spread about? I heard that evil ultimately had its place in his creation and design in order to further influence the goodness of the world when combating their great enemies, that’s how Eru wanted it to be like.

Given what I’ve said begs the question of; is Eru really All-Good? I’m not sure if I’d say it like that, of course, Eru is 100% incorruptible and perfect and is not under the category of what one would consider a “malevolent” deity. He’s seemingly on the good side, as Melkor/Morgoth is destined to be defeated for good with the potential remaking of Arda, in which it will not be marred by Melkor. And Eru is evidently supportive of the Valar.

An incredibly important thing to remember is that the concept of morality came from Eru, he made the concepts of good and evil, with good being the one Eru took side in, but ultimately, Eru is transcendent and above such concepts, as he is to any. He’s the author to his story, he’s pleased to do whatever he wants, everything in the story happening runs at the course of the author’s wishes (God/Ilúvatar). Eru Ilúvatar is at least more honest than the Abrahamic God whom he was based upon, hence why I find him to be a much better and greater character than the latter supreme deity.

And thou, Melkor, shalt see that no theme may be played that hath not its uttermost source in me, nor can any alter the music in my despite. For he that attempteth this shall prove but mine instrument in the devising of things more wonderful, which he himself hath not imagined.'

-The Silmarillion, Ainulindalë

Ultimately however, why he was like this with his plans nobody can give a concrete answer to, the goals of an omnipotent are beyond our comprehension. Even the Ainur themselves are unable to comprehend it, as it is mentioned later in the text, right after Eru made the statement above. The only entity who can truly comprehend The One is well, itself.

I am Eru Ilúvatar, The One, All-Powerful and All-Mighty, all things answer to me.

-Cesar Alcaraz