Stuck in initialising the experiment and cannot find the error

URL of experiment: Pavlovia

Description of the problem:
We have written an experiment in builder in psychopy3, including several code components. It’s a simple reaction time task plus a dictator game.
It runs smmothly in local, but when I upload it to pavlovia, it stuck in the “initialising the experiment” page.
I have went through the “Python to JavaScript Crib Sheet”, and made necessary changes according to it. I remove all "import” codes, manually transformed “None”, but nothing changes.
I have viewed several topics which have the same problem, some users say that we can use developer tools to locate the error. But when I paste my js code in the console, it says error in the line “import { PsychoJS } from ‘./lib/core-2020.1.js’;”, the error message is “Uncaught SyntaxError: Unexpected token {”.
I am totally new to python and java, so I cannot figure out what goes wrong. I will be very grateful if anybody can help me!

I am not sure if this can lead to my gitlab page

I think I have used the developer tool in a wrong way, now I can locate the error.