OnePlus devices are good but they just don't bring anything special IMO. If OnePlus made Google's hardware then it'll definitely be a strong contender. But things like call screening, assistant, now playing, the camera, 90hz screen, face unlock, motion sense, etc. Makes for a solid experience. And I'm more of a Samsung fan. But the Pixel 4 is the first Pixel I can actually use as a daily device. It's funny that the Pixel 4 is probably the most hated but happens to be my favorite.
All those things you just listed other than motion sense and call screening are available on the oneplus, and in fact One Plus 7 Pro had a 90hz OLED screen before the Pixel did.
Here is what I have found in the difference between the 2
Pro's of the Pixel 4xl.
Feel in hand. This phone feels amazing and it is the first phone I have had in a long time I have not felt the absolute need to put a case on.
Camera is great. I will need to look at some photos on a larger screen, but the lowlight is amazing
Always on display. I have always missed this feature on OnePlus phones
Esim is fantastic. I was able to add my work number to the phone without waiting on a Sim card.
Flat Screen. Personal preference, I prefer flat to curved edges.
The Speakers are a bit louder
That is really about it in comparison to the OnePlus.
Cons of the Pixel when compared to the OP7 Pro
Battery Life. The OP7 isn't great with battery life, but the Pixel is worse
Charging speed. Along with worse battery life, it takes almost twice as long to charge.
No finger Print reader. This is self explanatory but goes along with...
Spotty support for FaceID: I have to constantly use my password on apps that are not updated to use FaceID
Face ID also Opens the phone when I don't want it opened
Performance Issues. I think If I had not had such a perfect experience with OnePlus on both the 5 and 7 Pro I would not have noticed. But on the pixel, I occasionally get a lag on app openings to the point where I wonder if I hit the app icon or not.
Gestures on the OnePlus are in my opinion superior. Especially the Screen off gestures you get.
OnePlus Dual Sim implementation and ability to switch sims from the control shade is much better.
No 4k60 Recording.
There are some other little things that bug me. Like not being able to assign the squeeze to something other than assistant. And a Marque feature of the Pixel is the new Google assistant, but it will not work if you are using a Gsuite account on the phone. (If anyone knows a work around let me know.