Who are the in-universe creators of the Eternals in Marvel Comics?

If anyone reading this has tried to follow the last decade of changes to Marvel's cosmic history, please email me because I have a lot to say. Kirby started with simple intentions. The Eternals were created by the Celestials, 2,000-foot armored space gods who showed up a million years ago. Weird, but understandable. So obviously, Marvel went ahead in 2017 and made the Celestials the creation of the First Firmament (retcon #1). Then a year later, we found out the Celestials didn't make the Eternals for fun (retcon #2) or humans with the mutant gene on purpose (retcon #3). It was because they wanted assistance in fighting off the Horde, these weird cosmic bugs that killed the Celestial who crash-landed on Earth and is now responsible for mutants (retcons #4-infinity). And don't even get me started on the Beyonders' retcons.