Just so I'm not double-posting, here is a link to a post from another thread:
https://bobistheoilguy.com/forums/threads/voa-castrol-edge-hm-5w30-d1g3.371981/post-6599393
The videos I linked to are queued to play from the relevant part, so you only have to watch a couple of minutes rather than the entire videos. He certainly makes it appear that High Mileage oil is definitely NOT snake oil.
After watching his videos and looking at these VOAs, it appears that focusing on the Oxidation values will tell us which oil has the most seal conditioning esters. From that standpoint, the Mobil 1 EP wins, followed closely by Valvoline EP.