I have 3 PC’s running optical display port cables, and 3x CATx USB 2.0 extenders running on CAT 6 from my rack which is 100 cable feet away to my KVM which is at my desk (so my laptop can be plugged in directly).
HDMI is very picky at higher resolutions over longer distances. 10m might work if you buy very high end cables with lots of shielding. Optical HDMI or Displayport cables tend to cost the same or less than high end AV HDMI cables and dont have the same issues. They can go 45m easy, because again, I have 3 doing so right now (at 4k).
its generally simpler to go from Display port to HDMI than HDMI to display port but yes you can get an adapter to do that.
Displayport includes HDMI as a specification so you can use a Passive adapter or cable. Going from HDMI to Displayport requires an Active converter, Several are listed in the description for the KVM’s on the site.