HDMI Switch ? Star Tech Model VS421HD20

As the title states have just a few quick questions.

I purchased the VS421HD20 (4 inputs and 1 output) by Star Tech out of Canada through Amazon, it says it can handle 7.1 surrounds and 4K @ 60hz.

My setup:

55" Sony Bravia XBR 900E
Samsung HW-Q90R Sound Bar 7.1.4
2nd Generation 4K UHD HDR Amazon Fire TV
BD Player non-4K
Retro Game System

HDMI inputs on the Sony can all support 4K at 30 Hz but only port 2 and 3 support 4K @ 60hz/HDCP 2.2/HDMI 2.0/HDR 10 and I need to know how to set all of this up.

Here is my thinking:

plug the following into the HDMI switch - Amazon Fire TV/BD player and Retro Game System

plug the switch into one of the two in ports on the soundbar

plug soundbar out to eARC/ARC on my Sony TV

now my final questions - the HDMI switch supports 7.1 surrounds, would it also support with the Q90R which is 7.1.4 or will the up-firing speakers not work?? Not all of my devices BD and game system are HDMI 2.0 or HDCP 2.2, I'm assuming the switch and the system will downgrade it to whatever the device can handle? I would rather have TV/switch and sound system that can support all future modifications and just have to change our devices rather than have to change the many expensive components.

I have left a voice mail with star tech just to follow up with their support team to make sure everything will work together.

Thank you for all of your help!