In general you'd use a mixer with an Axe-Fx Rig by setting your effects in the Axe-Fx to be 100% wet and the effect block's level control for the effect's relative volume, and from there you'd set your external mixer to max volume for both the core tone and Axe-Fx signal. This would allow you to dial your effects to a max of 50% mix while keeping your dry tone intact.
As for how to setup each effect in the Axe-Fx to work in that kind of setup, you could do it like this, with each effect set to 100% wet, using the level control in each block to control effect volume, to make it work like a traditional rack where every effect is in parallel.
If you're only using the Axe-Fx for post effects and only want to route your effects in parallel, you can keep things simple by routing blocks like this:
However if you want a bit more flexibility, I'd route parallel effects like this instead:
If you wanted each effect to process every effect that comes before it, like if you wanted your delay trails to have reverb as well as the main signal, you'd add extra signal routes like this:
Remember to set every effect to 100% wet and Bypass Mode for each block to "Mute In" as well.
I made a big effort-post on the Fractal forums a while back about this kind of effects routing here:
https://forum.fractalaudio.com/threads/clean-capable-w-d-w-foh-grid-routing-idea.183177/