I have both of the guns you use as examples...several of each, to be truthful. They work well suppressed and getting to that point is easy enough. The 10/22s are all about the same as far as suppression goes. The pistol is offered in several models, a couple of which now come pre-threaded at 1/2x28. I prefer the 22/45 over the standard MkIII (and prefer the Mk II to the III, but that is a different story) because the grip angle and controls are closer to my 1911s. You can get suppressed uppers for the pistol, as well as suppressed barrels for the 10/22. Either of those would offer greater sound reduction, as a rule, than screw-on cans. On the other hand, the removeable suppressors can be used on more than one gun, so you could use the same one on the rifle and the pistol which allows you to get by with only one stamp...until you opt to buy another.
There are quieter guns and the level of reduction will vary with the make/model suppressor as well as the ammunition you use. But the 10/22 is versatile and I've used the pistols for the past 40 years.
FWIW