Suggested architecture for rewrite a client desktop app written in python (pyqt) as a web app

I have a desktop client application written in python. I used pyqt to develop the gui. This application mainly works exploiting a bunch of very specific python libraries. In order to have data some services provided by a web server are used.

Now I need to rewrite this client app as a web app, because my real need is to allow users to use this application without downloading any software on their laptops.

My question is, in order not to waste all the work and all the code already written in python with pyqt and all this other libraries, in your opinion what's the best solution to adopt?

Keep in mind also that I spendt few days tring to figure out if rewriting the application with javascript and angularjs could be possibile, but I realized that its a lot of work to do and a lot of already written code to waste.

In addition could be django or flask a good idea also?

thanks in advance