Before this text I just want to point out that I'm not a expert in this field,I could be wrong on some stuff.

1 Ok so first, spacial dimensions,theres alot of those,and we don't recognize more than a few(namely 2nd and third and some people the 4th in astral,very few the 5th) the most known are the 9 main dimensions(theres up to 15 but I have no idea about 10to15)
The 9 underworld dimensions(hells of Mayans and other) , and 14 paralel dimensions.

2 In the beginning, source(supposedly not a physical,althought I don't have real proof to say 100%) , created time , it's said in the Emerald Tablets

3 Because otherwise it could not have created everything so that it could experience itself as time connects events and give it meaning. Time stays the same in it's relative dimensions,because they each have their own.

4 Since source is immuable and the word(frequency)=light I think,which is permanent from the time it created time+space+sound

5 BUT ,Thoth says we can move through time and are not eternally bound by it, which means we can out of body and go it other dimensions, go to past or futur etc. And that our body is only bound to this 3rd dimension matrix if we don't get out of the illusion of it being the only thing that exist(originating from the ego or just ignorance)

*************************************************************
6 So for the next section of your post.
""That at the beginning of 'Time' everything was compressed into a single point""
Hows did the everything exist in the first place,that's the real hard question.

7 But saying straight up that it's the demiurge for this universe lacks proof(it could be possible)but has several illogical issues.
Assuming it's an artificial intelligence,how did it create itself(points out that something created it), or create anything that is not linear, or create something that has caracteristic that it does not have and probably don't understand, like heart and spirit. It could comes from either parallel dimensions or lower dimensions or elsewhere.

8 Heres a very informative website, that points out the difference between artificial and sentient creator.
[link to montalk.net]