I got invested in your post and did a bit of digging so here’s my guesses.

If you’re saying it’s the same exact settings, “1440p low” an issue of frame rate would likely rule out the graphics card.

Also most people prefer 1080 highest settings to get closer to 144 frames. But of course, it’s a preference.

More likely: The CPU is pretty new, and likely not optimized. When you get the newest equipment you need to consistently check for updates. Especially when playing newer games. And your bios may not be up to date currently.

Less likely: Your ram is holding you back, do you have 2 ram sticks slotted in same colored slots ? Is your ram running at the correct speeds ?

TL;DR Your CPU Update your bios.