Your mirror is down, bro. Interesting work, but are you running that on Win10? As you stated the sideloading crack doesn't work. There are theoretical "other methods" for bypassing store block so if you're willing to upload me and some others would sure be interested in giving it a try. HRTF encode files are the "spatial sound" processing libraries and HRTFs (Head-related transfer functions) are a method of simulating surround sound. Seems to show they have a "standard" for this spatial audio thing which both companies are following. EDIT: I was able to get version 1.12.0.0 to install but not 1.12.0.70 as that package was encrypted ;-;.
x.x.x.70 probably will be the same version. This is a case with any package from store, x.x.x.0 are not encrypted, x.x.x.70 are encrypted.
Does anyone have DTS Sound Unbound 1.3.3 APPX - or any version from 2018 / 2019? I've searched for it all over the web, @alanfox2000 had a MEGA.nz link that's down :/ Bless <3