Reducing Engine Braking

There is quite an abrupt slowing down of the engine when I shut off. How can one reduce engine braking please?

This is quite normal. You could reduce it potentially by not using over run fuel cut off (so that the engine is still actually running). If you have drive by wire throttle then you could very slightly increase the throttle targets at the rpm range you're noticing this issue - This would be when the accelerator pedal position is zero. Obviously modifying the dbw targets needs to be done carefully as the engine power may not reduce sufficiently if your targets are too high. I'd make changes of 0.2-0.5% maximum while testing this.

What is your ignition timing on overrun? This can affect the amount of engine braking you are feeling.