Is the OmniBook X Flip 16 good for gaming?

Only for light and older titles. It has Intel Arc integrated graphics and no dedicated GPU, so demanding games run at low settings and frame rates.

Can I upgrade the RAM or storage later?

The 32 GB of LPDDR5X memory is soldered and cannot be changed. The 1 TB SSD is a standard drive and can be replaced with a larger one.

Does it come with a stylus?

HP does not include a pen in the box for this model. You need an compatible active pen sold separately to write or draw on the touchscreen.

How does it compare with a 14-inch convertible?

It gives you a much larger screen and a numpad, but it is heavier and less comfortable to hold as a tablet. Pick the 14-inch if portability matters more than screen space.

Is the Core Ultra 9 288V fast enough for video editing?

For 1080p and light 4K cutting it is workable, but exports and effects rely on integrated graphics and will be slower than on laptops with a discrete GPU.