How to programatically create a Modal in React 18 - reactjs

Question

I did a function that creates a modal programatically for React 17, where you just needed to call a function to create a new modal.
It was working fantastic before the ReactDOM.render was deprecated.
Is there a way to replace the render function with something else in React 18? Right now the createRoot function is only for the root component, I want to render simple components in a specified DOM element.
It worked like this:
app.jsx
<button onClick={() => createModal(<h1>I'm a component inside a modal</h1>)}>Open Modal</button>
It handles it's own state, very useful if you want to make a bunch of modals in seconds.
This is the code:
index.js => Here is the container.
import React from 'react'
import ReactDOM from 'react-dom'
import './index.scss'
import App from './App.jsx'
ReactDOM.render(
<React.StrictMode>
<div id="modal-container"></div> <- This is the container
<App />
</React.StrictMode>,
document.getElementById('root')
)
Modal/Modal.jsx => The modal component.
import { useState } from 'react'
import './Modal.scss'
const Modal = ({ content }) => {
const [isOpen, setIsOpen] = useState(true)
if (isOpen) {
return (<>
<div className="modal-background" onClick={() => setIsOpen(false)} />
<div className="modal-content" >
{content}
</div>
<button onClick={() => setIsOpen(false)} className="close-button" >Close</button>
</>)
} else return null
}
export default Modal
Modal/index.js => The call function:
import { render } from "react-dom"
import Modal from "./Modal"
const createModal = (content) => render(
<Modal key={Math.random()} content={content} />, document.getElementById("modal-container")
)
export default createModal

Answer 1

It worked using createRoot this way, instead of render:
Here is an example: CodeSandbox
Modal/index.js
import { createRoot } from 'react-dom/client'
import Modal from "./Modal"
const createModal = (content) => {
if (!window.modalContainer) {
window.modalContainer = createRoot(document.getElementById('modal-container'))
}
window.modalContainer.render(<Modal key={Math.random()} content={content} />)
}
export default createModal
It checks if createRoot on the specified component has been called before, so it only call createRoot once, and the render function any time a new modal is created.
If you have a better answer it would be awesome too. :)