You’re on the right track with that setup guide.
In Logic, you can use the Utility I/O to send audio to/from the H90: https://support.apple.com/guide/logicpro/use-io-utility-lgcef2d8c7d2/mac
You’ll need to match up the inputs/outputs of the audio interface to the send/return channel in the Utility I/O plug-in.
Let me know how it goes.
