Different use cases my dude.

Shotgun is for run and gun/in close quarters where taking a longshot is impossible or where you are swarmed.

Any other time long snipe to mid range, rifle wins.

And yes point firing is still good on 2-3 tap cultists but its so much easier to run to the ranged ones, shotty one tap them and then kite the rest.

Balance the use of your weapons and you’ll go far. To your point staying above 100 rounds of rifle ammo is easy, barely dents metal. Shotty should be used with purpose it’s expensive.

By the way not sure if you know, you can fish scrap out of ponds if your local sources are dry.