Show file if exists otherwise redirect, but only for specific directory

Hi, I have a website that exists to forward traffic to the English version of the main website. Now I would like to forward every traffic from that site, except requests to specific directory.

Logic should be something like:

1. if not https, redirect to https
2. if request is for .well-known challenges, let to current server
3. if request is for file with location "language", let to current server
   1. if file exists show file
   2. else show default file
4. every other...

Show file if exists otherwise redirect, but only for specific directory

from Apache https://ift.tt/2x3DwbW
via IFTTT