Aren't there some hardware dongles to translate from DP to HDMI?
DP is something like a free superset of HDMI, so you can use a fully passive DP-HDMI cable. Obviously the feature set will be limited, but it will work.
DP however can't transfer audio, which doesn't matter for a desktop but matters a lot for a TV.
Last I checked, even the best ones that are high quality don't support VRR.