Nginx, https and voice assistant

When trying to use the microphone to speech input to HA assist, I need to have a https connection.
I realized that by having a letsencrypt certificate to my dyndns url and internally pointing my dns (pihole) to the local IP. That works for internal connection.
However, if I connect from outside using a wireGuard VPN, the URL can not be resolved - I believe because it’s resolved to the external ip of my router.

Now I am planning to install nginx as reverse proxy and ssl connect to nginx instead. However, this would mean the connection between nginx and home assistant would go back to http. Will I still be able to use my microphone?