Re: 2018 is the year of stupidly sized phones
"However, Sony aren't making an XZ3 Compact"
They [i]do[/i] make the 5" 1080p XZ2 Compact, however.
"XZ2 only had a Snapdragon 650"
Both the XZ2 and XZ2 Compact use the SD845 SoC.
While I'm here....
"The XS will survive a short dip in the deep end of a pool[...]"
Please stop with this twaddle. Every pool I've visited that has a "deep end" has it because of diving boards, and is therefore at least 3m deep. This greatly exceeds even Apple's generous 2m/30mins IP68 rating. IP68 is proof against sink/toilet drops, pub misadventures and heavy rain, nothing more.