Visual Studio 2022: Custom template won't replace parameters (and appears twice)

Question

I have two problems going on here: My template refuses to come in with the option to replace variables, and over the course of trying to fix it the template now appears twice.

First problem: Replacing template variables doesn't work

I tried creating a template for a file, since I will be adding a similar file two dozen times over the course of December. The template looks like this.

namespace $rootnamespace$
{
    internal class Day$dayNumber$ : DayBase<$outputType$>
    {
        public Day$dayNumber$() : base($dayNumber$) { }

        public override int FirstProblem()
        {
            throw new NotImplementedException();
        }

        public override int SecondProblem()
        {
            throw new NotImplementedException();
        }
    }
}

However, when I try to use it from the Add New menu item, it always comes out like this.

namespace AdventOfCode2023.Problems
{
    internal class Day$dayNumber$ : DayBase<$outputType$>
    {
        public Day$dayNumber$() : base($dayNumber$) { }

        public override int FirstProblem()
        {
            throw new NotImplementedException();
        }

        public override int SecondProblem()
        {
            throw new NotImplementedException();
        }
    }
}

Unzipping the template file, I find this, which looks correct.

And the template file itself looks like this.

<VSTemplate Version="3.0.0" xmlns="http://schemas.microsoft.com/developer/vstemplate/2005" Type="Item">
  <TemplateData>
    <DefaultName>AdventOfCode2023.cs</DefaultName>
    <Name>Advent Of Code 2023</Name>
    <Description>Advent of Code 2023 template for a day's problems.</Description>
    <ProjectType>CSharp</ProjectType>
    <SortOrder>10</SortOrder>
    <Icon>__TemplateIcon.ico</Icon>
  </TemplateData>
  <TemplateContent>
    <References />
    <ProjectItem SubType="" TargetFileName="$fileinputname$.cs" ReplaceParameters="true">Day1.cs</ProjectItem>
  </TemplateContent>
</VSTemplate>

ReplaceParameters is there, so I can't figure out what's missing.

Second problem: Old template still in list despite being deleted

Over the course of trying to fix this, I ended up cleaning up the XML above. Specifically, I added spaces in Name and fleshed out the Description under TemplateData. However, now I see the template twice in the available list, once for the old and once for the new:

I have checked both OneDrive and my VS templates folder, and so far as I can tell no duplicates exist anymore, just the one I have. Anyone know how to fix this? Maybe clear a cache or force VS to rescan for templates?