Managed to figure out how to use javascript on the plugin page by utilizing data-controller as found in other repos. Unsure how this is used, but appears to be how you can attach a js file to a div. Also implemented a basic state api to build off of in future.

Jellyfin.Plugin.MediaCleaner/Controllers/StateController.cs

@@ -0,0 +1,22 @@
+using Jellyfin.Plugin.MediaCleaner.Data;
+using Jellyfin.Plugin.MediaCleaner.Models;
+using Microsoft.AspNetCore.Mvc;
+
+namespace Jellyfin.Plugin.MediaCleaner.Controllers;
+
+[Route("mediacleaner/state")]
+public class StateController : Controller
+{
+    private readonly PluginState _state;
+    public StateController(PluginState state) => _state = state;
+
+    [HttpGet]
+    public IActionResult Get() => Ok(_state.GetSeriesInfo());
+
+    [HttpPost("add")]
+    public IActionResult AddSeriesInfo([FromBody] SeriesInfo seriesInfo)
+    {
+        _state.AddSeriesInfo(seriesInfo);
+        return Ok();
+    }
+}

Jellyfin.Plugin.MediaCleaner/Data/PluginState.cs

@@ -0,0 +1,29 @@
+using System.Collections.Generic;
+using Jellyfin.Plugin.MediaCleaner.Models;
+
+namespace Jellyfin.Plugin.MediaCleaner.Data;
+
+public class PluginState
+{
+    private readonly object _lock = new();
+    private List<SeriesInfo> _seriesInfo = new List<SeriesInfo>
+    {
+        new SeriesInfo { SeriesName = "TestName", Id = System.Guid.NewGuid() }
+    };
+
+    public void AddSeriesInfo(SeriesInfo seriesInfo)
+    {
+        lock (_lock)
+        {
+            _seriesInfo.Add(seriesInfo);
+        }
+    }
+
+    public IEnumerable<SeriesInfo> GetSeriesInfo()
+    {
+        lock (_lock)
+        {
+            return _seriesInfo;
+        }
+    }
+}

Jellyfin.Plugin.MediaCleaner/Jellyfin.Plugin.MediaCleaner.csproj

@@ -22,8 +22,8 @@
   <ItemGroup>
     <None Remove="Configuration\settings.html" />
     <EmbeddedResource Include="Configuration\settings.html" />
-    <None Remove="Pages\home.html" />
-    <EmbeddedResource Include="Pages\home.html" />
+    <None Remove="Pages\*" />
+    <EmbeddedResource Include="Pages\*" />
   </ItemGroup>
 
   <PropertyGroup>

Jellyfin.Plugin.MediaCleaner/Pages/home.html

@@ -1,4 +1,5 @@
-<div data-role="page" class="page type-interior pluginConfigurationPage withTabs">
+<div data-role="page" class="page type-interior pluginConfigurationPage withTabs"
+     data-controller="__plugin/media_cleaner_table.js">
 	<div data-role="content">
 		<div class="content-primary">
             <div>
@@ -6,6 +7,15 @@
                 <a href="#configurationpage?name=Settings">Settings</a>
             </div>
 			<h2>Media Cleaner</h2>
+            <table id="seriesTable">
+            <thead>
+                <tr>
+                    <th>ID</th>
+                    <th>Series Name</th>
+                </tr>
+            </thead>
+            <tbody></tbody>
+            </table>
 		</div>
 	</div>
 </div>

Jellyfin.Plugin.MediaCleaner/Pages/media_cleaner_table.js

@@ -0,0 +1,27 @@
+var table = document.getElementById("seriesTable");
+
+
+
+const getMediaCleanerState = async () => {
+    const response = await fetch('/mediacleaner/state');
+
+    if(!response.ok){
+        throw new Error(`Response status: ${response.status}`)
+    }
+
+    return response.json();
+}
+
+var state = await getMediaCleanerState();
+
+console.log("State: ", state);
+
+for(let i = 0; i < state.length; i++){
+    var row = table.insertRow(-1);
+    var cell1 = row.insertCell(0);
+    var cell2 = row.insertCell(1);
+    var cell3 = row.insertCell(2);
+    cell1.innerHTML = state[i].Id;
+    cell2.innerHTML = state[i].SeriesName;
+    cell3.innerHTML = state[i].Seasons.length;
+}

Jellyfin.Plugin.MediaCleaner/Plugin.cs

@@ -2,11 +2,13 @@ using System;
 using System.Collections.Generic;
 using System.Globalization;
 using Jellyfin.Plugin.MediaCleaner.Configuration;
+using Jellyfin.Plugin.MediaCleaner.Data;
 using MediaBrowser.Common.Configuration;
 using MediaBrowser.Common.Plugins;
 using MediaBrowser.Controller.Entities;
 using MediaBrowser.Model.Plugins;
 using MediaBrowser.Model.Serialization;
+using Microsoft.Extensions.DependencyInjection;
 
 namespace Jellyfin.Plugin.MediaCleaner;
 
@@ -53,6 +55,11 @@ public class Plugin : BasePlugin<PluginConfiguration>, IHasWebPages
                 EmbeddedResourcePath = string.Format(CultureInfo.InvariantCulture, "{0}.Pages.home.html", GetType().Namespace),
                 EnableInMainMenu = true,
             },
+            new PluginPageInfo
+            {
+                Name = "media_cleaner_table.js",
+                EmbeddedResourcePath = string.Format(CultureInfo.InvariantCulture, "{0}.Pages.media_cleaner_table.js", GetType().Namespace),
+            }
         ];
     }
 }

Jellyfin.Plugin.MediaCleaner/PluginServiceRegistrator.cs

@@ -0,0 +1,13 @@
+using Jellyfin.Plugin.MediaCleaner.Data;
+using MediaBrowser.Controller;
+using MediaBrowser.Controller.Plugins;
+using Microsoft.Extensions.DependencyInjection;
+
+namespace Jellyfin.Plugin.MediaCleaner;
+public class PluginServiceRegistrator : IPluginServiceRegistrator
+{
+    public void RegisterServices(IServiceCollection serviceCollection, IServerApplicationHost applicationHost)
+    {
+        serviceCollection.AddSingleton<PluginState>();
+    }
+}