The general consensus in the AV1 community is that the SVT encoder implementation isn’t ready for HDR(10+) yet. There are some other encoders of AV1 (including Netflix’s proprietary implementation) that can do it well but basic SVT offered through the public repo is not ready for HDR yet.
Edit: I should add that I compress most of my library in 1080p with av1-svt. I only leave a couple of titles in 4k format and those I’m waiting to rip until SVT becomes mature enough to handle 4K.