Nothing special, But I found it to help fix my ADS issues.
Please Note: This is not a fix to all around performance or optimization. You will find the game still lags. However, This has directly fixed my frame drops due to ADS.
Open Geforce Experience, Click Borderlands 3, And click custom settings to the right of Optimize button
Slide the slider to desired position, I chose to put mine in the middle, Leaving me with most settings still on high, While increasing the performance.
Here is a list of what my slider had changed the settings too. Note I changed Anti-Aliasing to FXAA, Picture does not show this change)
I tried many fixes people have listed, As well as lowering the in game Overall Quality setting to very low and increasing the desired settings. Was still experiencing ADS frame drops. Once I did this, I stopped having ADS issues. Sit around 120 FPS before and after ADS
Hope this helps you guys some.