maybe?

config/ember-try.js

@@ -2,20 +2,25 @@ const getChannelUrl = require('ember-source-channel-url');
 
 module.exports = async function () {
   const ember5Deps = {
-    '@ember/string': '^3.1.1',
-    '@ember/test-helpers': '^3.2.0',
-    '@types/ember__test-helpers': null,
     'ember-cli-htmlbars': '^6.3.0',
     'ember-cli-babel': '^8.0.0',
-    'ember-qunit': '^8.0.0',
     'ember-resolver': '^11.0.0',
-    '@types/ember-resolver': null,
-    'ember-auto-import': '^2.3.0',
-    webpack: '^5.88.2',
     'ember-cli-dependency-checker': null,
     'ember-maybe-import-regenerator': null,
     'ember-cli-app-version': null,
+    // These tests deps are kind of entangled
+    '@ember/test-helpers': '^3.2.0',
+    'ember-qunit': '^8.0.0',
     qunit: '^2.20.0',
+    // required for ember 4+
+    'ember-auto-import': '^2.3.0',
+    webpack: '^5.88.2',
+    // required for ember 5+
+    '@ember/string': '^3.1.1',
+    // not needed anymore, because the corresponding packages
+    // ship their own types
+    '@types/ember__test-helpers': null,
+    '@types/ember-resolver': null,
   };
 
   return {

package.json

@@ -53,6 +53,7 @@
   },
   "devDependencies": {
     "@ember/optional-features": "2.0.0",
+    "@ember/test-helpers": "^2.9.4",
     "@glimmer/component": "^1.1.2",
     "@glimmer/tracking": "^1.1.2",
     "@release-it-plugins/lerna-changelog": "^5.0.0",
@@ -64,17 +65,15 @@
     "@types/console-ui": "2.2.6",
     "@types/core-object": "3.0.1",
     "@types/debug": "4.1.7",
-    "@types/ember": "4.0.1",
-    "@types/ember-qunit": "5.0.0",
-    "@types/ember-resolver": "^9.0.0",
-    "@types/ember__test-helpers": "^2.9.1",
+    "@types/ember": "4.0.6",
+    "@types/ember-resolver": "^5.0.13",
     "@types/esprima": "4.0.3",
     "@types/express": "4.17.13",
     "@types/fs-extra": "9.0.13",
     "@types/got": "9.6.12",
     "@types/mocha": "10.0.0",
     "@types/node": "14.14.31",
-    "@types/qunit": "2.19.3",
+    "@types/qunit": "2.19.6",
     "@types/resolve": "1.20.1",
     "@types/semver": "7.3.9",
     "@typescript-eslint/eslint-plugin": "5.10.1",
@@ -98,7 +97,7 @@
     "ember-export-application-global": "2.0.1",
     "ember-load-initializers": "2.1.2",
     "ember-maybe-import-regenerator": "0.1.6",
-    "ember-qunit": "4.6.0",
+    "ember-qunit": "^7.0.0",
     "ember-resolver": "8.0.2",
     "ember-source": "~3.28.0",
     "ember-source-channel-url": "^3.0.0",