I think I found a solution :
I tried several php and nginx settings, it appears to work after adding the following in my /etc/nginx/sites-available/cloud config file in the container, in the location ~ \.php(?:$|/) section :
fastcgi_send_timeout 600;
fastcgi_connect_timeout 600;
proxy_connect_timeout 600;
proxy_send_timeout 600;
proxy_read_timeout 600;
send_timeout 600;
Note that my NC instance runs in an incus container behind an nginx reverse proxy. I also added some of those parameters on the host side.
After (tens of) hours of testing, I must admit that I haven’t kept track of all my files changes.
Correct me if I’m wrong : I naively understand that the NC desktop client uploads the first 100 files one by one, then by packs of 100.
The timeout occurs if the sync of a 100 pack files takes too long.