Maldekians

[Raukura Waihaha]

I doubt that, because if they fell back to 3rd density, they would have had to evolve to 6D before the current earth master cycle (which is supposed to be the 1st one) since they talk about all the major cycles and harvests here.

What sounds more likely is the Venusians who didn't evolve with the Ra complex probably ended up at Muldek. Ra obviously has karmic ties to our greater history (including Muldek and Mars) which is why they came originally in the past and recently. It certainly feels like they are obscuring alot through the LoC.

Ra says that the planet wasn't 3D habitable until 75,000 years ago. That could mean that after the destruction of the Maldek civilization 700,000 years ago, it wasn't until 75,000 years ago that the planet could support 3D life again.
"Falling back to 3D" or relearning choices made behind the veil is something that doesn't necessarily take as long as natural 3D progression, without outside interference.
There was an ascension event in South America 25,000 years ago, before 4D conditions were the planetary norm. I feel it's possible to reach 6D within 3D cycles using ascension techniques and having certain frequencies boosted with pyramids etc.