one laptop install ubuntu 18.04,apache,nextcloud.LAN speed is 1 Gbps. just configuration webdav in apache.here is part of site 000-default.conf file,nothing is superfluous.
Alias /dav /var/www/dav <Directory /var/www/dav> DAV ON require all granted </Directory>
Download speed is good,about 110MB/s,but the upload is slow,about 25-35MB/s.
I try use many diffence software:winscp,raidrive,firefox; diffence environment:windows10 on my desktop , android phone, and one ubuntu virtual machine(bridge mode) running on the windows10; diffence method:apache dav,nextcloud dav,browser, they work the same.
Try to upload to the virtual machine,speed is 80MB/s.so router should not is bottleneck.
iostat -x 1 when upload to laptop ,the %iowait is jump between about 0 or 9.9.
What to next .