A:Answer This document has the wall mounting information you're looking for on page 7:
https://downloadcenter.samsung.com/content/EM/201910/20191016075851665/BN68-09856A-01_UM_QRQ50O_ZA_ENG-US_190808.0.pdf
The VESA pattern is 100 x 100 mm. Bolts are M4, 19-22 mm. Thread pitch is 1.25 mm, standard for M4/M6/M8 VESA mount hardware.
I believe this is the correct information, my 32" Q50R has a 100 x 100 mm hole pattern. I do not have M4 bolts, but can confirm that M6 bolts are too large.