Translate Desktop Application to Web Application

I made a desktop GUI application using PyQt5, matplotlib, and seaborn. I want to have the same exact thing on a website so the user can navigate through the application through the website instead of having to download the exe file. I can't find any way to do this in which I don't have to redo the large majority of it. Is there any way to translate this without having to redo the entire GUI?

I've looked at python web frameworks like Flask.

I've looked at PyJs but don't completely understand it. Do I still have to do the graphical aspect of the application in HTML (and CSS)?

Is it even possible to run the matplotlib and seaborn plotting libraries on a web browser?