Question About Custom Pass Blur

This is UI Blur in the custom pass example.
use CustomPassUtils.GaussianBlur.


This is an image made using Photoshop Filter - Gaussian Blur.
I don't know the exact name,
It's also called like Frost Glass Effect




Of course,
i can create a similar feeling by increasing Radius and sample count of the custom pass Gaussian Blur

But there is two problems.

Q1) The bright areas are too emphasized.
Unlike other programs(Photoshop, After Effect, or etc) Blur filter,
contrast is very strong, and the bright part shines so intensely.

Q2) Performance is so expensive

I can also able to produce good results using this two method
- Using HDRP Unlit Shader's Distortion Blur
- Using Shader Graph Full Screen Pass HD Scene Color LOD
However, these two methods were not available in the Custom Pass After Process UI.
(Is there any way?)

I also changed the downsampling, but it didn't seem to solve the problem.

To sum up my requirements
1. Blur should also be applied to objects that are injected into the After Post Process
2. Blur that blends well so that it doesn't stand out too much should be operated with meaningful performance