Does your amp support CEC? If so, you could make sure it is turned on for both ATV and the amp and just use the “HDMI” setting in the ATV settings.
Also, just to confirm—in the ATV’s remote>volume control settings, do you have it set to control the receiver via IR?
MAYBE you could make an argument if my Mac screen was in vertical portrait layout all the time, you could begin to argue in favor of the thought process behind the current design.
But without that, with a landscape-oriented Mac display, the argument just isn’t there, so the thought process doesn’t make sense.
This is all before you even brain storm actual UI design ideas—the base-argument is invalid.
If you end up copying the photo library file to an external volume, be sure to hold down “option” next time you launch photos.app—that will let you select the new location for the photo Library.
Move your photo library from ~/Pictures to an external storage volume with enough storage space. Then, either turn off iCloud Photo Library and allow the process to download all you photos or just export like you were doing to the external.
Why do you want to back them up? The iCloud sync is pretty good, unless you are worried about deleting photos yourself by accident and not noticing during the 30-day window that they would still be in the “recently deleted” directory.
This isn’t a big deal.
If you’re developing in Xcode, you did not buy an 8GB Mac in the last 10-years.
If you are just using your Mac for Facebook and email, I don’t think you know what RAM is.
If you know what RAM is, and you bought an 8GB Mac in the last 10-years, then you are likely self-aware of your limited demands and/or made an informed compromise.