Access restriction to Admin site with language selector in URL

We prevent access to our Admin site and various other urls using http authentication at the web server. However, with Django, there is a language selector slug as the first part of the url

for example:

where es could be any of hundreds of languages.

It’s fairly easy to filter with a regex on the web server - looking for a two character or 5 character language string. (en, en-US, en-AU, az, es, fr and so on).

Cloudflare access doesn’t allow wildcards in the urls - so I can’t see how I could migrate the html auth rules over to Cloudflare access. unless I’m missing something?

Any suggestions on how this might be achieved or a workaround done? It would be great to be able to move the access upstream.