Please help me find a precise size infuser.

As the title suggests, I'm looking for a very specific tea infuser. On Amazon there are these 15oz titanium camping mugs that have folding handles, a lid, and a tea infuser that sits snugly inside the mug. The issue, which has become my recent obsession, is that I want something about twice the size and cannot for the life of me find a compatible infuser.

For example, I have a Stanley Adventure cook pot, a 32-oz stainless steel milk frother, and various other vertical pots that are all around the size that I want. However, I cannot find a large enough diameter infuser to fit into any of them snugly. I've even gone as far as to collect a bunch of random stainless steel ramekins, bowls, and other nesting pots from thrift shops around town in hopes of fashioning one into an infuser either by drilling my own holes, or by tack welding something together custom. Alas, all of the objects I collected are either slightly too large or too narrow in diameter to work.

I don't want an infuser that sits on top of the mug or pot by utilizing winged tabs, and I'd prefer not to use a mesh teapot basket replacement unless I can absolutely find the correct size. I know this has transitioned from a hopeful DIY into a frustrated obsession but at this point it's driving me mad. At first I couldn't believe that this object doesn't exist, but then I figured it might exist but be utilized as something else such as a stainless steel drain basket for a sink or floor, a seasoning basket for a soup pot, a hop spider for brewing, a deep fryer oil filter, or a mesh pasta strainer, but still... none of these are the size I need.

For a 32oz milk frother I need an infuser that is 3 9/16" for the outer diameter (3 1/2" inner diameter), and no more than 4 3/4" in depth. Alternatively, for the Stanley Adventure pot I need an infuser that is 3 15/16" outer diameter (3 11/16" inner diameter) and no more than 5" in depth.

Can anyone help me find this thing, or am I better off purchasing raw materials and tack welding this thing together myself?