Most holsters will "scrape down the insides".
That's just the nature of holsters whether they're leather, custom fitted leather, Kydex, or anything else.

You might get less by buying a custom fitted holster from a top maker.
Don Hume makes excellent holsters, but they're primarily holsters built for cops who don't have a lot of money.
The Hume Jordon holster is todays version of the "Border Patrol" police holster designed by Border Patrolman Bill Jordon.
In the 60's through the 80's it was the default police holster in America.
It will probably be no better then the Hume holster you have now.

To get a custom fitted holster you're going to have to spend a lot more money, but the finish on the gun will wear just about as badly.
Even having the holster lined with suede, pig skin, or even smooth leather will not save the finish.
In fact, suede linings are known to catch and collect dirt and grit in the rough texture and scratch and wear the finish even worse then a holster with just a smooth finished interior.

If you don't want the finish worn, never holster the gun.