Who do you think Tom Bombadil really was

[Tuor in Gondolin]

Interesting view of Bombadil as Eru, but there are problems.
In The Council Of Elrond:
(Glorfindel)

...even if we could, (take the Ring to him unobserved)
soon or late the Lord of the Rings would learn of its hiding place and would
bend all his power towards it. Could that power be defied by Bombadil alone?
I think not...

(Eru less powerful then Sauron)?

And in Letters #144 JRRT sees Bombadil as renouncing control, taking a
"vow of poverty" in a form of pacivism. Not at all the continued involvement
in Middle-earth in the Third Age (sending the Istari, having the Ring fall
off Gollum's hand just in time to be found by Bilbo, putting elvish words
into Sam's mind) all of which would seem to have been either at Iluvatar's
instigation or at least valar initiatives approved by the One.