How's the search going? As you know from my other posts I've been also trying to find a good solution for spatialization on Quest. I've tried Resonance and it seems to work but the spatial definition seems quite bad. I have to double check my settings but so far Oculus Audio is the one that gives the most realistic spatialization. Why would they have it low in their priority list? I've tested Oculus Audio on Unity (the only game engine they seem to favor) and it works great on Quest... but I don't want to use Unity. Unreal has Vulkan support and better visual results and production tools The last time I checked Steam Audio had no Android support in UE4 but now that I'm checking the documentation it does mention Android. I'll give it a try.
So I tried Steam Audio and at least the spatialization works on Quest, but it's very far from the localization quality that you get with Oculus Audio and at close distance it behaves incorrectly as if the source is always very wide.
If what mean is what to do with the audio spatialization situation in UE4, then basically you can use either Resonance or Steam Audio, which are not the greatest but might be good enough for what you want (particularly if your audio sources are distant). You could also use the native Unreal Engine spatialization but I've experienced strange sound localization at certain listening angles and positions.
How about performance on Quest when using Steam Audio ?
I am not sure about using Resonance since Google already killed their VR initiative.
I didn't test much more than playing a single audio source, without any occlusion setup (which seems to be available for Android/Quest with Steam Audio) since I was mostly focusing on spatial image quality. In a simple scene that has about 1 million polygons of static geometry I didn't notice a difference between Steam Audio and Resonance. I'm also reluctant to use Resonance due to the same reasons, although there is at least one developer still overseeing the project but it doesn't seem to advance much with the Unreal Engine integration (their repo is still based on 4.19). On the other hand, it seems that Epic is doing some work on it as I was told by one of their developers that in 4.23 they did a bunch of changes to add more platforms support. I think it would be great if Oculus open sourced their Oculus Audio SDK, in that way at least we could try to fix things for Unreal Engine. I've also considered taking the Android libraries from Unity and using them to fix the Unreal implementation, there's even a 64 bit one:
But it all depends on how generic they are keeping their API. It might not work at all for Unreal.