My front disc brakes are rubbing despite my efforts
It sounds like your pistons are failing to retract when the brake lever is released.

The mechanism used in bicycle hydraulic brakes to advance the pistons as the pads wear and to retract the pistons slightly when the brake lever is released is flexible rubber seals that surround the pistons. The seals deform as the pistons are pushed forward then pull the pistons back as fluid pressure is released.

It may be that your seals or pistons need cleaning. Check out this Park Tool video that shows how the seals work and how to clean them.