Salut
Your speeds resemble the speed of my old and slow Synology DS-110J.
Bud even then the COPS home page is show fater (if the HDD is spun up, if not then 30 sec+ is to be expected.
I tested with a COPS database containing about 20.000 titles.
I accessed COPS over LAN (gigabit) with Firefox in Private mode.
On slow hardware the "recent additions" page takes forever to show
all the thumbnail images. If cached it takes way less time.
On faster hardware (Intel Pentium G2120 + SSD for the OS) running Debian 9 (Linux) and Apache 2.4 and PHP 7 the home page is shown almost immediately (1-2 secs). The "recent additions" page takes a few seconds to display and some more time before all images are loaded (titles to display is set to 1000).
On a WAMP like installation (UWAMP) on Windows 7 (32 bits) on a 10 year old AMD dual core COPS is significantly slower than with Debian.
I think for you the WAMP-server is the limiting factor.
Try to speed up WAMP server (maybe remove the cgi_module) or search on the internet for a solution that works for you.
Or is your LAN slow?
Also check if your server CPU is at 100% (on all cores) while it is busy displaying the "recent additions" page.
Hope this helps.