Extra error with Invalid operand for a '+' operation

Author: alexrecuenco

eslint.config.mjs

@@ -1,10 +1,12 @@
 import eslintPluginAstro from 'eslint-plugin-astro';
 import tseslint from "typescript-eslint";
-
+/** @type {import("@typescript-eslint/utils").TSESLint.FlatConfig.ConfigArray} */
 export default [
-  ...tseslint.configs.recommended,
+  {ignores: ["*.config.*"]},
+  ...tseslint.configs.strictTypeChecked,
+  ...tseslint.configs.stylisticTypeChecked,
   // First issue, eslintPluginAstro MUST be defined after, since it overrides the typescript parser
-  ...eslintPluginAstro.configs['flat/all'],
+  ...eslintPluginAstro.configs["flat/all"],
   {
     rules: {
       '@typescript-eslint/await-thenable': "error",

src/pages/index.astro

@@ -24,8 +24,12 @@ const b = 0;
     const c = null!;
     const d: any = 1;
 
-    const element = document.getElementById("my-root")!;
-    element.offsetLeft += 4;
+    // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
+    const element = document.getElementById("myroot")!;
+    // no error
+    console.log(element.offsetLeft + 4);
+    // error  Invalid operand for a '+' operation. Operands must each be a number or string. Got `any`  @typescript-eslint/restrict-plus-operands
+    console.log(element.offsetLeft += 4);
     console.log(d);
     console.log("c");
     const container = document.querySelector(".container")!;