Aspect Ratio Not Available When In YouTube

Recently purchased an LG model OLED65CXPUA TV, replacing my PANASONIC PLASMA HDTV, model TC-P60ST60. Problem is my viewing screen is reduced (Cropping) by about 28 percent when watching YOUTUBE / YOUTUBE TV movies on my LG TV. The Aspect Ratio is not available when in YOUTUBE. Did not have this problem with my PANASONIC, just accessed the Aspect Ratio and adjusted the screen. This is a TV specific software problem, not a movie content issue that according to LG technical support cannot be fixed. What can be done to fix this software issue?