Pro box doesnt support Dolby Vision though right, so the content on Apple that is mostly all DV will need to fall back to HDR10. Which is simple enough as Vision is a meta layer ontop of normal HDR I thought. Based on the description of the OP that it is tagged as DV in the app but doesnt present as such, seems the app is not ported for the EETV that well.
Content on Prime however ive found is nearly always HDR10, Netflix favours more Dolby Vision content also.
The above is my experience however with the equipment I use, Apple TV (Box) with those apps, I dont use EETV apps.
-----------------------------------------------------------------------------------------------
BT900 | Nokia ONT | Ubiquiti ER-X | EETV Box Pro (IP Mode) | Unifi CK2 | 6x Unifi U6+ | 2x Unifi SAK Ultra
