youtube have quite a number of reviews liao? local reviews will probably need some time since most got their phones yesterday only. haha.
I've not tried any of the newer sony though. last one i bought was the xz2 premium. But if you want my guess, the OP8T will probably still be better value ba since even local sets are like S$4XX cheaper than the Xperia 5ii, and both running SD865. But sony probably still have more premium hardware features like official ip65/68 rating, 3.5mm jack, better camera hardware, better screen. Also i kinda like their battery care stuff like charging limit, bypassing battery charging while gaming and plugged in. So have to see whether you need those features lor. But feel like oxygenOS might still be nicer to use though, and OP8T if go for local set will have 2 years warranty?