Really slow upload and download speeds.

[kbarbora]

Before I say anything, thanks for awesome work on this series of repos.
I setup the proxy and others docker containers (wp, nextcoud, portainer),
however the nextcloud (NC) is giving me really slow upload (max 10mb/s, avg 6mb/s) and download (6mb/s).
I tried in two different networks, one in the same LAN (via ethernet) as my NC server (traceroute looks like is going out of my LAN and come back) and other network where I have bandwidth of 1GB/s and I obtained same results on both.
Doing a web search people suggested to disable HTTP/2 in nginx (I have not tried it yet).
Comparing to my previous NC setup which I have a 3TB HDD I can almost utilize the full capability of ethernet (100mb/s) on uploads.
My proxy/NC server setup is 1TB SSD with intel xeon 2690v3 (12c/24t) and CPU-Usage during upload/downloads is not a bottleneck (less than 10%).
Anyone have a suggestion idea of what could be the issue?