SP4 owner here, you should avoid the pro 4, one of its revision (with the samsung display) is very prone to touch screen defects, see this issue.
I’m avoiding surface in general now, after using linux-surface for a year, I finally gave up and got myself a thinkpad x1 tablet. Even without the touchscreen issues, my experience with my SP4 was never good, the cameras needs libcamera and are awful, audio input randomly stopped working after sleep,I had blackscreen issues after login, and random freeze.