No, he's going off the already understood knowledge of the object. You're making the assumption that it could mean some lower dimensional understanding of the Source for some lower realm, so you'd have to prove it.
The Source Wall has been stated to exist everywhere, this scan is an example
Additionally, the Source Wall has been shown countless times to exist at the edge of every universe, this being an example
So I have already established that the Source Wall exists everywhere, and also borders every universe, not just the total Multiverse. It exists in all dimensional levels. This is why we don't consider feats of destroying the Source Wall to be 1-A by default. I don't have to definitively prove that Lucifer visited a universal source wall, I have provided a possibility and based it well, and since Deagon is arguing for a higher interpretation, the burden is on him.
But that's what the debate, currently is about, as it does indeed relate to the scaling of Lucifer and Michael. So no, it wouldn't be derailing.
It is related to their scaling, however it's not something currently accepted. This relation is currently accepted differently, with the Presence being divided into Yahweh and the Divine Presence. So this requires to change something else from the CRT other than what is currently accepted. It requires its own CRT.
But that's if it's already specified that a character is from a lower level to the point where them going beyond the source wall would be through outside interference, outliers, or because of it extending to a lower level. It doesn't make it an automatic assumption we can make for every single feat.
Why doesn't it? We know that the Source Wall exists in all dimensions, and universes. A Source Wall destruction feat can be destroying the Source Wall bordering a universe, or going beyond it can be going beyond a source wall bordering a universe. Saying it refers to the absolute source wall is a total assumption.
POTM also made it clear here-https://vsbattles.fandom.com/wiki/User_blog
rinceOfTheMorning/DC_Cosmology_-_From_a_Holistic_Stance_on_the_Overall_Canon#:~:text=Characters%20cannot%20be,lower%2Ddimensional%20level.
It is addressing it to say that it isn't a very strong argument considering that you didn't apply any evidence to support the notion that it would apply to Lucifer and Michael's feats.
Because the burden is not on me. I am claiming a lower interpretation and has provided a base to the interpretation being a possibility. By default, higher interpretations need to be proved, not lower ones. The lower ones are the default takes.