Very nice. In my book the dihedral effect is a stabilizing one, i.e. acting in opposition to a roll disturbance.
We agree easily that the dihedral effect on a swept wing is magnified with increasing AoA.
The discussion seemed to revolve correctly about a cross-over speed, where lift available at aileron centre of pressure creates moment insufficient to counter the lateral lift imbalance introduced by yawing a swept wing configuration, the airplane tries to capsize.
Your dihedral effect, the power of which increases with AoA, acts in opposition to that.
Lower speed when yawed takes you closer to that snap roll point.
Lower speed at constant path means higher AoA.
Higher AoA provides for stronger anti-roll effect as explained.
Forensic evidence shows even that is not sufficient and nothing saves once you go too slow.
Nothing wrong with discussing cross-over speeds.