Infuse does support DTS-HD MA and TrueHD, and the full lossless audio will be sent to your receiver as LPCM.
The decoding process itself is standardized between all Dolby/DTS certified products (Infuse is certified and licensed for both) so in the end there is no difference whether this decoding is done by Infuse or your receiver. A bit more info on this can be found here. Audio Options & Capabilities – Firecore Support
The only real caveat is Infuse is not able to support Atmos or DTS:X due to limitations in tvOS, but this is something we are encouraging Apple to change. A few more details can be found here. Help get (more) Dolby Atmos on Apple TV