Does this TV have Ambilight?

Yes. It has three-sided Ambilight that projects colors from the screen onto the wall behind it. You can set it to follow the picture or use fixed colors.

Is it good for gaming?

It is a 60 Hz panel with no high frame rate or variable refresh rate support, so it suits casual console play but not competitive gaming. Check that your console's output matches the HDMI inputs.

What is the difference from the previous Philips 75-inch model?

This model keeps 4K, HDR and Ambilight but adds Dolby Atmos decoding and HEVC playback. It still lacks wide color gamut and local dimming, so the picture is close to the prior generation.

Can I mount it on a wall?

Yes. It is VESA mountable, so a standard 75-inch wall bracket works. Check the bracket's weight rating against the TV's weight before mounting.

You get the TV, a stand, a remote and a power cable. HDMI and other cables are not included, so plan for those separately.

Does it support Dolby Atmos?

It decodes Dolby Atmos, but the built-in speakers are stereo, so you get Atmos processing rather than true overhead sound. A soundbar or receiver gives the full effect.