Web Vitals displays unstable metric data

[maxming2333]

Environment

self-hosted (https://develop.sentry.dev/self-hosted/)

Steps to Reproduce

Question 1：

1. Enter Insights -> Frontend -> Web Vitals, select the project and a absolute date, such as the absolute date area of ​​the previous month
2. And then the LCP and FCP data will be displayed.
3. However, if you refresh the page, or click on the FCP detailed data to view, the LCP and FCP data of the page will change dynamically, and you can finally see that the FCP and LCP data statistics are very unstable.

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Our team cares more about the real data of FCP and LCP, because some of our optimization data need to be compared through sentry, but if this statistical data is unstable, it will lead to misjudgment.

When any conditions remain unchanged, if the interface is just requested repeatedly, different data will appear. This interface is not idempotent and will lead to many problems. I hope it can be solved

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Question 2：
In addition, there is a strange phenomenon in one of my projects. FCP data is larger than LCP data, which is not possible normally.

Expected Result

Web Vitals results are stable and unchanged

Actual Result

With the same conditions, Web Vitals results will change continuously

Product Area

Performance

Link

No response

DSN

No response

Version

25.2.0.dev0

[getsantry]

Assigning to @getsentry/support for routing ⏲️

[getsantry]

Routing to @getsentry/product-owners-performance for triage ⏲️