Hi @anthony_COPPET, welcome to Nextcloud community 
please use search many issues have been discussed already, especially check the tags traefik reverseproxy setup_warning and Frequent Nextcloud 29 (Hub 8) update issues
I would recommend you start simple
- remove all the middlewares you added, this might cause some issues (especially -trailingslash)
- review reverse proxy docs, I think you are missing some attributes