Search should find podcasts in other languages, no matter what your app setting is set to. You can change the app language in the settings (see below). To change your suggestions in the Browse tab you will most likely have to change your Billing Address as suggested per comment.
You can simply select the language in the settings app.
settings app, locate the
Podcasts tab and set your
preferred language. Simply open the Podcasts app and search in English. Results will now show English podcasts.
If this does not work, use the Feedback App to report back to Apple that there is a bug, since it is working for me on iPadOS 14.4.