Case and fan shim

I have just purchased a Raspberry Pi 4B. Having read articles on cooling I plan to add a fan shim. I would like to mount the pi vertically (for best cooling). Is there a case I can buy that allows good air flow? Size is not important and I would like to keep most of the dust out. I am using it in a normal home environment.

Any case you use is going to have to have good ventilation, as in holes for air to go in and out. Otherwise you’ll just be blowing hot air, ;). That being said some dust is going to get in. You’ll just have to blow it out etc from time to time.
I use the Pibow Coupe cases which have a cutout specifically for the fan shim. They work well for me.

I also so have one of these on my Pi 4B 8 gig.

That Pi runs a little hotter than it would with a fan shim, but not enough to be a concern. I’m seeing ~50c under moderate load and ~35c idle. The advatage is no fan to make noise or wear out, and only surface dust on the outside to clean up.
And no impact on my WIFI as hear as i can tell, there is a gap where the Pi’s antenna is.