I’ve been thinking / asking about this type of stuff too. See https://www.modulargrid.net/e/forum/posts/index/10312 for a lot of ideas and resources
I’m going to get Expert Sleepers ES-3&6 as that will give me I/O via ADAT all run through my RME interface. So that saves me the “2 interface” issue which I don’t want to t try to deal with on my PC based setup. As I have ADAT lanes to spare this is IMO the simplest and tightest solution for my setup. If I needed more I/O there are add ons like ES-5 etc that can be added.
BTW stepping up to a good interface such as those from RME or UA etc is a big step up for your studio.
Hope this helps, cheers!