I didn't have the problem for the last 2 days after the update. I had the My Verizon app installed the whole time. Just a few minutes ago I began to have the 20 sec delay. Instead of uninstalling the app, I just forced stopped it and the delay went away.
Until the app is fixed, just force stop it. It worked for me, your mileage may vary....
I was hoping that the update to the My Verizon app that I received yesterday might resolve this issue, but it didn't. Neither did removing and reinstalling the app, or using the Force Stop option. I like having instant access to information that the app provides, such as data usage; but this delay in initiating phone calls is intolerable. So I'm just removing the My Verizon app until they -- or someone here -- can find a solution that works on my P2XL.
I was WONDERING why I was having a huge lag on the P2 when placing calls ... thanks! I force stopped the app and will check to see if it works ... if not, I'll uninstall it for a while, then reinstall it.
I have the pixel 2XL and my other half has the Pixel 3XL. After the Android 10 update both phones would not dial out at all. No delay just would not dial out. We removed the My Verizon app on both phones and both phones now dial out.
I'd try uninstalling the T-Mobile app first. If that doesn't help, then uninstall Visual Voicemail. (You shouldn't need the latter anyway if you have a Pixel -- Google's own Phone app should transcribe your voicemails by itself.) I doubt T-Mobile Tuesdays would cause any problems.