programmatically insert text into a React managed div

I want to write a userscript for Tampermonkey, i.e. in vanilla JavaScript. The userscript should fill text into the div with the id “inputBoxSummarizer” on website https://quillbot.com/summarize. This div is a React-managed.

When I set the innerHTML of that DIV, I briefly see the text inserted, but then react refreshes the DOM.