Help choosing compatible theme for additional backend work

Hi there
I need a wordpress theme for my wesbite, however I need to alter the backend code to add some features. My coder is most proficient in python, so what are my options in terms of themes?
I’ve been reading that wordpress themes are all coded in php and I don’t want to run into problems, could someone provide some clarity please?

thanks

Yes, WordPress is written in PHP so if you want to do some advanced customization, find a WordPress developer.

I don’t have to use wordpress, can be any except shopify that provides themes - just need that ability to write in python. Any recommendations?

Then you should look outside of Envato. WordPress, Joomla and Drupal are the most popular CMS with themes sold here and all of them are written in PHP.

This CMS is written in Python if I am not mistaken
https://www.django-cms.org/en/