Based on input from @Sandroid, I took the liberty of amending this wish/report with a bit more context. @thephatconductor, hope you don’t mind, and if you do, please feel free to remove the added parts.
However, I have a question:
What does this mean exactly? To my knowledge, the delay only has a low-pass filter, so there is no way to clean up the lower frequency range. I filed a separate request for the equivalent of this request but for the Delay: Expand Filter capabilities on the Delay effect