So far so good (a few weeks) using the 240hz internal display and the uperfect montior at 144hz connected using usb-c /nvidia gpu. YMMV.
OS/drivers/software/accessibility settings could all matter. So much discussion of that on this forum already. And their is also the panel lottery situation as well.
I one point I tried using an usb capture card connected an e-ink android tablet as a DIY alternative to dedicated e-ink monitors for text only work but it was way too slow, bad contrast, etc. Those dedicated e-ink monitors also still have a long way to go but seems to work for some.