Just remove the PS. There is no real way to make a weapon called Power Sword that needs to be functionally on par with mundane weapons.
Power blades do more. If you are going to have them, they need to be better than a knife, shovel, axe or fancy name sword. Chain weapons can be adjusted with being slower due to more bulk. Power weapons go through power armor and vehicles.
" Only the most powerful and influential warriors of the Imperium possess a power weapon as a result of their rarity. Inquisitors and high-ranking commissars or Astra Militarum officers tend to possess them, as do members of various noble families with potent political clout and wealth. The Space Marines make use of many of the power weapons in existence, as is their right."
This weapon needs to be replaced with a Burning Blade
Burning Blade
What started as a series of malfunctioning power swords from the disreputable Clovis Munitorum became a new weapon type after users discovered the swords’ faulty field conduits raised the temperature of their blades to over 600 degrees Celsius.
Loi Metalworks investigated and created what are now known as “Burning Blades,” power swords that deliberately create intense heat along their blade so as to burn flesh to the bone with each strike.
Heavily insulated so that the user feels little of the inferno raging inches from their palm, these swords are nevertheless extremely dangerous to the wielder as well as their opponents.
Targets hit with this weapon are likely to be set aflame. A commonly employed variant of this weapon is known as the Loi Pattern.
OR
Shock Baton
This weapon expands with a flick of the wrist from a small, easily concealable rod no longer than the width of a hand to a slim eighteen-inch long club. The weapon contains a tiny shock generator that can generate five Shock discharges before it requires recharging. It is common amongst undercover investigators who wish their quarry to survive for interrogation, and occasionally finds its way into the armouries of more secretive organisations like the Inquisition.
IMO, these are the weapons they are trying to make the Power Sword into. It is a relatively simple and elegant solution. Re-skin and rename.