I posted this on Reddit and thought I'd share here. If you have a Pixel 6 Pro and have apps that are very slow to open when on carrier data, this may be for you.
Having been working from home since I received my P6P, I never really spent much time off wifi. Over the past few months, however, I have been noticing certain apps like NHL, McDonald's, Subway, Gas Buddy, (the list goes on) that when launched, they take a very long time to finish initial load. I even ranted on the Twitters blaming McDonald's for a sub-par app. Yesterday I thought I'd try one of my test Bell 5G sims in my P6P to see if there was any difference. To my surprise, the Bell sim worked fine. I swapped my Telus sim into my test Galaxy S22 and it worked fine in that device. I called Telus and as expected, they were pointing their fingers at my device. I then tried a different Telus sim in my P6P and same result - slow. I tried my sim in my wifie's S23 Ultra and it worked fine there. This led me to believe it was something with Telus and my device. I googled "telus and pixel 6 pro" and came up with the above link. After changing my APN settings, it was like night and day. Problem solved. Telus checked the settings and agreed that they were ok to use. I suppose I will follow up with them again to ask why I need special undocumented APN settings for my P6P but I hope I can help someone else with this info. This has been driving me crazy for months and I did not want to have to reset my entire device and spend a weekend customizing it back to my preference.