Client: LG WebOS
My tv supports DV fine but I don’t see the option to select DV with files that support both DV and HDR.

Client: LG WebOS
My tv supports DV fine but I don’t see the option to select DV with files that support both DV and HDR.

You cannot select DV or HDR10.
Plex will try to play Dolby Vision. If it cannot, it will try to play HDR10. If that fails, it will try to transcode HDR10. If it cannot transcode HDR10, you will receive an error message.