I find the number of variables in mutes so frustrating! I've settled on NordyMutes & rather than fit it 'perpendicular' I angle the foam so it travels along the strings, pointing towards the nut. Also, sitting deeper on lower strings & barely touching on the higher. No mods needed, removable, reasonably easy to recreate, and about the best I've found for a not-overkill & consistent muting across the strings without too negative an impact on intonation.
I can recommend experimenting with the "Danny Mo Morris" 2nd+3rd+4th fingers on fretting hand technique, and just a simple "immediately release the pressure to stop notes sustaining"... though it takes far more patience and practice to master than I have 😢