How can I connect the same headphones to the audio outputs of two different devices?

Question

Headphones

There are two devices: PC sound card (analog and optical output) and PS4 with optical output.
There are headphones.
I would very much like to be able to have some kind of device (or other way) to connect my ears to both devices at once with the ability to choose which channel to listen to.
Those. have some kind of splitter (conditionally) on the inputs of which there is a signal from the sound system (analog or optics) and a single from PS4. And the output is an analog signal to the headphones with a choice - the signal from which device should actually come to them.
After some study of the issue, I did not find an adequate solution - either amps for a lot of money, or bundles of several devices.

Answer 1

Is connecting the PS4 to the line in of the sound card not an option?

Answer 2

Perhaps a small simple mixer will help, for example:
www.music-market.biz/shop/i1523.behringer_mx_400_m...