I've seen this issue with DP cables a lot over the past few weeks across multiple different GPU's PC builds and monitors.
The solutions haven't been easy and are heavily based on the exact brand and model number of your monitor also if the DP cable has the bandwidth capability to support the amount of information passing through it.
First thing I would check is if the monitors firmware is fully up to date.
I think a lot of people facing this issue have gone to HDMI monitors.
Could be design flaws in the DP cables themselves or hardware and software support just haven't caught up to DP cable abilities.
Truthfully, I have no experience with DP cables only VGA DVI and HDMI fiber optic digital coax standard coax (RJ 6) (Cat 3 5 and 6 for telephone and data) Plus a whole host of electrical wiring for both AC and DC based power systems.
I know a community member with DP cable and port experience will reach out to you soon.
Don't worry we will help get this issue resolved.