Memes

If “every point in the universe originated from the exact same point” then that origin point is somewhere in the center of the universe

This is where I'm disagreeing. Since space itself is expanding, every point "originated" where it currently sits, and has "expanded in place" so to speak. You can't really imagine this as an expanding bubble (the balloon analogy was bad here), since a bubble necessarily expands into existing space. In our case, the bubble itself is the space.

tracing the trajectories of every point backwards should intersect somewhere very close to that point.

That's where you get a problem. Space is expanding, so if you pick an arbitrary point in space, you'll observe that the universe appears to be expanding out from that point. No matter where you are, and what direction you look, you will see that everything is moving away from you. Thus, if you reverse that process to "trace it backwards", then no matter where you stand, you'll see everything contracting towards you, and conclude that you are at the centre. For reference, Hubble agrees with this interpretation.

Saying “sometimes physics is mindboggling” in order to rationalize invalid leaps is not a strong argument.

I'm not trying to make any bombastic claims and hand-wave them away with "physics is hard". I'm trying to give an accurate recollection of the current consensus based on my own understanding of it (which is rudimentary at best).

Honestly, if the concept of time breaks down when you look at t=0, then that only tells me that the idea of t=0 itself is invalid and needs to be abandoned.

It breaks down within our current models. You can of course always ask the question of "what happened before X", and the answer today is that our current models can take us more or less arbitrarily close to a singularity (t=0), but not all the way there. There are several theories out there regarding what the "initial state" was.

Time didn’t just magically start at some random point before which time didn’t exist. And space didn’t just magically expand into 3 dimensions before which there was only 0. (...)

I'm not really saying it did. I'm saying that, as far as I know, we have no better model or understanding than that if we extrapolate to t=0, we get a singularity (0 D), that for some unknown reason "magically" started expanding into the 4 D space-time we inhabit today. The fact that this process violates pretty much every known law of nature really just means there's something here we don't understand yet. I believe it's pretty well established that our current models more or less completely break down at around the Planck time (see the "in cosmology" section).