Congrats on the new setup! There are many ways you can use the H90 and the Triaxis together, so somebody else may suggest another configuration. Below are some ideas I would try:
H90 in Triaxis FX Loop:
Connect Triaxis mono FX send to H90 input 1
Connect H90 outputs 1-2 to Triaxis stereo FX return
Connect guitar directly to amp input
Turn Kill Dry on
All of of the H90’s processing will be after the preamp, in the FX loop