2019 great x265 4k settings?

[jlw_4049]

I like to rip my BluRays and encode them into smaller file sizes for my PLEX server.

I've been doing 1080p for years, while I'm pretty informed I have only just hit the tip of the ice burg.

I use handbrake to encode on my home server/plex machine.

I am looking for near lossless quality for 4k with a nice size reduction. I know that you lose quality encoding anything etc.

I have encoded some 4k clips with handbrake with the settings CRF 24, 21, 19, 18, and 17 @slow.

So far 19 feels like the best option in my opinion for the most part but I was wondering if you guys had any better options.

1 more question, is slow worth it over medium. Since medium is technically double the speed.