This is similar to how mine is set up. Except only the mixing board mains go to a RME. Because of the number of synths and exterior hardware, I use 4 MOTU Midi TimePieces that give me a total of 32 midi in/out. You can network 2 Motu Midi TimePieces for 16, so my PC will "see" that as 2 sets of 16. Obviously, 2 Clockworks. Cubase will "see" it as 32 in/outs.Every synth has its dedicated midi connection and routed audio line ins. (You can imagine how much cables fly around here). It then goes to AD converters that are wired with my server room. So, in my DAW I simply select the preconfigured midi channel in my template and start playing on my master keyboard. That's all. Plays like a soft synth - easy on your CPU with nice analog sound
I barely change knobs on hw side, since I use synths in a different context than others.
And since I'm using an old Behringer MX8000 24/48, (don't laugh, it's lasted 20 years and I only use it to monitor mostly synths) 48 channels is enough for everything to be permanently connected. If I feel the Behringer is degrading something, then I can go direct via a patch bay to the RME. Then, yes, my DAW template has a MIDI channel for every hardware piece that accepts midi.
As far as trying to enhance workflow, I feel my bottleneck is with my rack synths. Nord 2, Matrix 1000, EmuMorpheus, TX802, D-550, EnsoniqSQR, Roland SRV-2000 and a KorgMS2000. None of these, with the exception of the Nord, are as immediate as a keyboard synth. I have to open MidiQuest, open the configuration, then browse/edit the library.
I should sell half of this stuff, but I see the ridiculous high prices. Then my brain flips from artist side to investment side.