Ttn Webhook for Nextcloud Phonetrack App

I wonder if there is an easy solution to integrate a ttn device that sends gps locations into nextcloud apps like “phonetrack” or “maps”.

The available http endpoints in the apps are either based on GET requests or the delivered JSON Data in the POST request does not match the expectations of the app.
Apparently the ttn webhooks can’t be configured to send GET requests?

Any ideas without involving another service?

For example i could run a little script that does the expected requests based on mqtt messages. But it would be nicer without.