The Pixel 3 and Pixel 3 XL are the company's third generation Pixel smartphones and they were slated to be the best it had to offer. Sadly, the two smartphones have received mixed reviews with some criticism focusing on the smartphone's performance. A software feature called Digital Wellbeing also debuted on the Pixel smartphones with these devices and some users are saying that disabling this service helped fix the performance issues they were having. Not only that, but others have agreed and even say it helps on other devices as well.

Pixel 3 XDA Forum

The reports of bugs and performance issues with the Pixel 3 and Pixel 3 XL aren't a secret. They were so bad when the smartphone first launched that we pooled them together to detail the biggest ones we could find at that time. Since launch, other issues have been reported, but performance related ones were getting most of the attention from the community. It wasn't widespread, but it was bad enough that the issue continued to make headlines throughout the year.

As most of these issues can have multiple culprits, we never were able to pinpoint the issue for all users, but one person on Reddit recently published their findings on the Digital Wellbeing application. See, this is an application that is built to control your app usage as well as catalog major activities that happen on your smartphone. So it makes sense that this service would be running in the background a lot. This could cause the service to eat up CPU cycles which could be attributed to the infamous performance issues.

Pixel 3 XL XDA Forum

Trueray17 posted in the /r/GooglePixel subreddit about how they disabled usage access of the Digital Wellbeing service. With that one, they were able to navigate through the OS without noticing any lag or stuttering at all. In fact, they say the UI is "buttery smooth" for them after this change. While this may not be the reason everyone is experiencing these issues on Pixel 3 and Pixel 3 XL, it has shown to help a lot of people (even those without a Pixel smartphone).

Source: Trueray17