one thing to try - and martin_au reminded me that all deirect extruder setups have different length filament paths.
Check the retraction settings.

I remember reading that those extruders you have do have a very short path. so you want a correspondingly short retraction length.

So maybe 1-1.5 mm. probably at 50-60mm/s for stiff filaments.
If the retraction length is currently set significantly higher than that - then it could help cause the blockages.

Damn good froggy :-)

What sort of purge wall does it use ?
Or can you get away without using one ?