zxkl,
it depends what you mean by "Sooloos software" - something I do not believe we are clear about yet.
There is no doubt that the end-points provide very high sound quality. They must include a very effective collection/buffering/assembly stage which I assume provides an opportunity for dejittering. Most of that must be software-based.
There is the (semi-proprietary?) network comms software which allows the stores, core and end-points to communicate. I cannot see how/why that would affect sound quality once it has ensured that packets arrive in a timely fashion at the end-point, but it is clearly essential and specific to the Sooloos ecosystem.
The import software does something special to ensure as-near-perfect-as-possible rips, which I would presume enhances sound quality. Export and back-up, less so.
The rest is the music searching/management/metadata (including the supply of metadata) software which does not affect sound quality but may affect enjoyment.
All the above relates to Sooloos up to 2.2.
The scope of Sooloos 3.0/Roon is not clear to me at all.