render_template does nothing after receiving ajax content (flask, python, javascript)

I am passing data with ajax to my python function when a condition is met:

        if (lesson.length === 0) {
            $.ajax(
                {
                    type:'POST',
                    contentType:'application/json',
                    dataType:'json',
                    url:'http://127.0.0.1:5000/result?value=' + errors ,
                    success:function(response){ document.write(response); }  
                }
            );
        }

I know that the information is correctly received, since I can see it in the terminal through print:

127.0.0.1 - - [19/Aug/2020 11:59:46] "GET /static/flexjava.js HTTP/1.1" 200 -
0
127.0.0.1 - - [19/Aug/2020 11:59:48] "POST /result?value=0 HTTP/1.1" 200 -

But python does nothing after the print() function. Render or redirect both don't work, the browser stays just as it is even though the information was passed:

@app.route("/result", methods=["GET", "POST"])
def result():
    content = request.args.get('value')
    if "username" not in session or session["username"] == "guest":
        return redirect("/login")
    if request.method == "GET":
        return redirect("/")
    else:
        print(content)
        return render_template("finished.html")