I haven't tried it yet, because I'm still waiting for my Redmi 5 Plus. I found this in another forum, google it and install the .apk file:
GoogleCamera-Pixel2Mod-Arnova8G2-V3 (Arnova8G2, 2018-01-30, changelog)
Go to settings --> advanced --> Config Camera HDR+: Nexus 6 Auto (the only config that works).