Hi Les112
The one power is now set to on in Settings on the 360 box, but still no differnce.
You also need Simplink (HDMI-CEC) enabled in Settings > General > External Devices > HDMI Settings (I would also set HDMI Deep Colour to 4K within the same section) on your LGC4.
I also have an LG C4 (OLED48C46LA) which is currently running Software Version 23.23.05 and have no problems with the menu bar on the 360 Home Screen and font, although sometimes it can be difficult to read due to the actual static image VM are showing on that screen.
The actual 360 Home screen is always changing. It's a bit like the Home screen on the LG which keeps changing with different promotions and recommended content, and sometimes that screen can also be difficult to read.
It may boil to the actual settings you are currently using on your LG C4. For example if you have Energy Saving turned on then the screen brightness and text is always appear darker and may be difficult to read.
The screen brightness for text and images may be more manageable and clearer depending upon the Picture Mode you have set on your C4. Using the Auto Power Save mode means the images will be dimmer and text will be harder to distinguish.
I would say the same applies if you have it set to Standard mode, however each of us has their own preferences and the brightness of the actual room your TV set is in, even at different times of the day can determine the mode you are using.
I have mine set as Sports mode the majority of the time, although I also switch to Vivid mode for certain programs/times of the day/and equipment. (My firestick and firecube can look a little washed out depending what I'm watching and which apps I'm using until I change modes on the TV)