I recently got a monitor that has 144hz only with displayport. However, my laptop only has one hdmi connection and therefore I'm wondering whether it is possible to use an adapter with dp in order to be able to get this 144hz.
You could kaifen a 144hz hdmi cable and a 144hz adapter
HDMI 2.1 can achieve a maximum of 120Hz at 4k resolution, which you can't extrapolate even with an adapter, that does not help, because a conversion can't improve quality.
So you need HDMI to DP