This is a long YouTube comment addressed to someone in particular.
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You're overly attached to this mistaken objection of "that's a blunder." There is no blunder here. If you disagree, I would encourage you to write a short essay with a brief logical analysis, maybe quote some philosophers who disagree with you and respond to them, and then submit your paper to a secular philosophy journal.
The "blunder" appears *only* if we're talking about entirely contingent realities (since no contingent reality could explain itself), not with the concept of a necessary reality -- IF (some version of) PSR were true. By "contingent" I mean something whose non-existence is possible and by PSR I mean the idea that there's an explanation for everything that exists.
PSR is very controversial and I am not here endorsing PSR, but instead trying to help you understand why the "blunder" isn't a blunder if our model includes PSR. Look at it this way:
1. If some version of PSR is true then the *totality* of reality has an explanation.
2. PSR is true.
3. So the totality of reality has an explanation.
4. If the totality has an explanation, this explanation cannot be contingent (i.e it can't be something whose non-existence is possible) because we would then need an additional explanation as to why this thing (which may have failed to exist) nevertheless exists.
5. So the existence of this explanation must be *necessary*/ its non-existence must be impossible given (3) and (4).
6. If the totality of reality has an explanation, that explanation cannot be exterior since we would then be positing something external to the "totality" of reality, which is a contradiction.
7. From (6), the explanation for the totality of reality must be (in some sense) *within* the totality of reality.
8. Therefore, some aspect of the totality of reality (X) serves as the explanation for the totality of reality.
9. However else we describe X, it cannot depend on anything beyond itself because *that* would then be the explanation for the totality. (Infinite regress mentioned later)
10. So the explanation of the totality is an explanatory *ultimate* and stopping point. There is no further existential explanatory source beyond X.
11. From (2), (9), and (10), the explanation for this stopping point/X must reside in itself, i.e. X is self-explanatory exists by a necessity of its own nature, or i.e. its non-existence is metaphysically impossible.
12. Some aspect of reality is self-explanatory.
13. If X is necessary and self-explanatory, then X exists because of X (which is *not* the same claim as "X caused X").
14. X is necessary and self-explanatory.
15. Therefore X because of X.
I wrote this in a hurry and if I had more time and inclination then I'd probably polish and sharpen it. Rasmussen, Feser, Koons, Hart, etc. would have made this clearer and more succinct. Either way, PSR (if true) and the nature of contingent reality will ultimately take you back to an explanatory ultimate that is non-contingent and exists by a necessity of its own nature-- self-explanatory.
If you want to insist that this is a blunder, then IMO it seems you are committed to a denial of any and all forms of PSR. In which case, I'd simply recommend Feser's chapter on PSR in his 2017 book "Five Proofs" under the title "The Rationalist Proof."
To be fair, one can grant some form of PSR and concede a necessary/self-explanatory stopping point for the sake of argument and then simply deny that this necessary reality has the properties normally ascribed to the God of classical theism (as Dawkins, Oppy, etc. have argued). That's a separate discussion.
Also, if someone were inclined to insist upon an infinite regress they still wouldn't avoid the issue of "X because of X" since we can apply PSR to the infinite regress itself. So even if there's an infinite regress that just is the explanatory ultimate without any explanation outside of the regress, then we would still be saying "X because of X" -- in this case, infinite regress because of infinite regress. For the record, I don't think infinite regresses of any sort would satisfy PSR, but that's another topic for another day and isn't relevant to the overall point being made here.
NOTE: Again, at this point I am not trying to argue for classical theism. I'm merely attempting to explain a scenario in which "X because of X" isn't a blunder.