UM84R Bianchi DA revolver holster; crossdraws...
I'd check out the well engineered Bianchi UM84R holster for your 4" barrel K frame revolver. It can be worn strong or crossdraw in either hand & has a flap(removeable). It's based on the rugged M12/UM92 military holster in use for over 30 years.
The Bianchi Ranger line is impressive too. They can be toted strong/cross-draw.
If you want a custom rig or have the $$$, there are a few good designs from shops like; Kramer, Don Hume, El Paso Saddlery, Andrews Leather, Galco, DeSantis, Blackhawk, or Milt Sparks.
Some holster makers use exotics like rhino, horse, shark, gator.
Speed's fine, but accuracy's final.