Up until a year or two ago, the majority of monitors (and graphic cards) used DisplayPort 1.4 and HDMI 2.1. With HDMI 2.1 (42 Gbps) having more bandwidth than the DisplayPort (26 Gbps).

This is my case with my relatively new/high-end RTX 4080 and OLED monitor. So until I upgrade both, I use HDMI to be able to drive a 1440p 240hz 10-bit HDR signal @ 30 Gbps.