Seems that it has been quite a while since Marvel has shown us that "GOD" actually does exist and runs things over in the MU...

Any one else remember these times though God was referenced in marvel?

Dr Strange being told by Eternity that he and Death rulked over 1 reality, Dr stranges, but that the being called GOD ruled over all realities and universes?

When Johnny Blaze was about to be taken down to hades, and a mysterious friend, who happened to look Exactly like Jesus, appeared and took him back from Mephisto?

When Dracula had trhe picture of jesus in the storyline, and he fought an Angel, who told him that his Master would never fight Dracula, sent him instead?
When Drac was made a Human for awhile, as by refusing to ackwoledge either God/satan, was stuck on earth in sort of limbo?

When both Thor and Odin have referenced there being a "Higher" power?

LT refernced that he was merely Agent of even higher powers that Him or Adam with the IG?

AND

When back in the early days of Marvel, my father showed me an issue when the Watcher said that the "messiah" was perhaps single most powerful being in the MU?

Seems that marvel used to have the concept of God being ok...

Just when did it switch to God no longer being referenced, or shown, but instead just as the unseen TOAA?

Also Doctor Strange once invoked God in a spell when he fought Dracula.

God was also referenced by the Gibborim in Runaways iirc.

"I am made of things your philosophy will never comprehend." -Loki

In Fantastic Four #511, (May 2004) the Fantastic Four go to Heaven and meet 'God' who appears in the form of Jack Kirby. And in Sensational Spider-Man #40, (October 2007) 'God' appears before Peter in the form of a homeless man.

They don't use the One Above All too frequently because he's too powerful an entity. He has to be written carefully because if you use him too often, it will raise too many problems and questions.

Your examples are mostly subtle and they don't spell out exactly that there is one true God and that it is the one we all think of now. Most references have been of a "higher power" type wording, which could mean Celestials for all we know. Only Christian-themed stories have really ever shown much evidence of this and even there it doesn't establish this religion over any of the other pantheons in the MU.

"I am made of things your philosophy will never comprehend." -Loki

...with the FF issue, the Fulcrum also took a human form and called himself Jack in a reference to Kirby.

How to make an entrance: https://www.youtube.com/watch?v=49xWJJvpjzI

Lord Majestros:
the only time TOAA has been seen in a comic he looked like Kirby as you noted.

Sorry no scans but it was Eternals #9, last series iirc. The pic above is from that issue where the Fulcrum(presumed to be the One Above All) meets with the Dreaming Celestial. You can do a wiki on the Dreaming Celestial for the full scoop.

"I am made of things your philosophy will never comprehend." -Loki

because to me nothing about the Fulcrum really supported it to be the supreme being. It stated it has sowed life on many worlds, but I do not recall any mention of it having created the multiverse. It's desire for a companion to explore creation implies there are worlds out there it didn't create and possible beyond it. It's name the "Fulcrum" implies it exists to maintain some sort of balance yet as far as I recall nothing about its "balance" made any real sense. All in all aside from perhaps being poorly thought out it comes across as just another nigh-omnipotent cosmic being.