First make sure your component file extension is .tsx. Then you would wanna tell TypeScript that your function is a React Functional Component, with the help of FC type from React:

import {FC} from "react";

const SisenseDashboard : FC = () => {

  const sisenseRef = React.useRef(null);

  return (
    <>
      <Box
        display="flex"
        flexDirection="column"
        alignItems="center"
        marginBottom={2}
      >
        <h2>In-App Reporting</h2>
      </Box>
      <Box
        ref={sisenseRef}
        id="sisense-container"
        className="sisense-demo"
      ></Box>
    </>
  );
};