EM busters

Many years of fighting EM beyond using a dedicated power spur have given me the following list of remedies ( by descending order of efficacy)
1. Acoustic Revive RTP and Power Reference power cable
2. Bybee Golden Goddess Speaker Bullets
3. Bybee Golden Goddess RCA Bullets
4. Akiko Tuning Chips and sticks
5. Acoustic Revive REM-8

While I use tweaks for grounding, impedance matching and vibration damping, my personal experience has shown the biggest bang for the buck in products suppressing EM.

My system: Innuos Zenith Mk3->Intona USB2.0 Industrial ->Antelope Zodiac Platinum plus Antelope Audiophile10m clock->Wavac EC300B->Duevel Bella Luna with Murata ES103.
Interconnects Artisansilvercables, Auditorium23, Powercables Nordost Valhalla and Brahma, speakercables Auditorium23

That is quite a system antigrunge2. I assume you listen to digital only? What genres do you like?
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mainly Classical, Jazz and Blues
I spared you the analogue bit: Scheu Das Laufwerk2 Slate driven by Verus Rimdrive with Dynavector DV507, Zyx Universe and Zyx Artisan on Auditorium23, Mørch UP4 12in with MC Scheu and Aqvox 2CIMk2 (balanced on Nordost Tyr)
I agree with the OP. RFI hunting and EMI reduction is key for good sound. A big step was with the JSSG 360 tweak from the computer audiophile website around DC cabling, Ethernet, usb and interconnects.
XLR, RCA, HDMI caps were also closing a pathway of RFI. And I use heat shrink on metal connectors. Cross contamination with stray voltages always happens at the entry points.