>>51685
And that's only three of them.

>>51686
Russets have a lot of starch is why. You'll have to mash them a little bit, but it will thicken it up. Another trick you can use is buying instant mash, just dehydrated potatoes, and throw that in to a soup and mix it up. It will thicken it up just the same, and you don't need to be autistic about it like flour or cornstarch. It will obviously give the soup some potato flavor but still. And dump too much you'll just start making flavored mashed potatoes.
There is potato flour too. I have a bag but never used it. I wonder how easy it mixes in.

Just get an immersion blender. They're easy to use if you aren't autistic. Otherwise yeah you could give that a try if you're going to throw potatoes in it. Might try adding half at the beginning and the other half later so you still have whole pieces of potatoes.