Reamp + Isolator with Triad TY-250P

Hi, I need advices trying to achieve this Reamp-Isolator box. The impedance matching is still a mystery for me, particularly from the preamp to the soundcard.

REAMP:
Soundcard (RME UFX+) -> Line Output / Balanced / 75 Ohm
to
Preamp (Steavens The Brick) -> Instr/Guitar / Unbalanced / HiZ

ISOLATOR:
Preamp -> env. 5Vrms / Unbalanced / 10 kOhm
to
Soundcard (RME UFX+) -> Line Balanced 12 kOhm

For the reamp, I don't need to mimic Guitar impedance. I just use the preamp as insert overdrive/distortion in my DAW.

Here is the schematic:
Capture d’écran 2023-03-08 à 09.46.04.png