You might try the newer version of that cable that supports DP 1.4 https://www.amazon.com/DisplayPort-uni-Thunderbolt-Compatible-MacBook-dp-B09HKL7M2N/dp/B09HKL7M2N/ref=dp\_ob\_title\_def?th=1

I had that exact same problem! I had used a dongle and that didn't work. the fix was, I bought actual cables, USB-C to DP. plugged in from the laptop to the monitor directly. I get a smooth 4k, 144hz on my monitor that is rated as V-SYNC compatible. I am not sure what your monitor has, but it is Freesync, it might not work with the NVIDIA GPU.

I bought these:

https://www.amazon.com/dp/B08BXPVPPQ?psc=1&ref=ppx_yo2ov_dt_b_product_details

https://www.amazon.com/dp/B09HKL7M2N?ref=ppx_yo2ov_dt_b_product_details&th=1

I think I am currently using this one:

https://www.amazon.com/dp/B09M38CXZ3?psc=1&ref=ppx_yo2ov_dt_b_product_details

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This absolutely DID NOT work!

https://www.amazon.com/dp/B085HNGLZR?ref=ppx_yo2ov_dt_b_product_details&th=1

​

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Beware the dongle!