Schmalle

I suggested to try the stereo blocks by which I meant: try the blocks in the stereo fx category. That doesn't mean that every one of those blocks works for what you want: Stereo (two channels that define a stereo field) isn't necessarily dual mono (two independent channels), but dual mono is always usable for stereo. My point was that it is expected that if you use mono blocks the inputs L and R will be mixed. Notice that this is the first time in the thread that you specified your use case in enough detail so that people can understand your point. Basically the limiting factor for you is that you're not being able to split twice - which tells me you're probably an HX Stomp (you didn't specify that either). Btw: For mixing your pickup signals as a Y-Split alternative (not Crossover Split) you can use the Volume/Pan(Stereo)->Pan block from the (or Stereo Width block if you want to be able to flip the phase). A mono block after it collapses it to one mono signal if needed.

That is all expected behavior. If you want to "create a proper bi-amping patch the way many bass rigs are built" nothing is stopping you from doing that after the split (usually a hard left-right panned Split Y, but a Crossover Split can also work - although it seems a bit radical). I mean you would set amps differently and probably choose different amps in a bi-amping situation anyways, wouldn't you? There are some very little DSP demanding amp sims like the Del Sol 300 if needed. https://benvesco.com/store/helix-dsp-allocations/

I'm not sure what you want. If you want to use effects on the lows and highs individually you can do that on their individual paths between the Crossover Split and the Mixer. The Crossover Split does what it's supposed to do. Say you use it and then combine both paths into one again with the lows on one side (L or R) and the highs on the other (by panning in the mixer block). If you then use a mono block both sides (L and R) are summed to a mono signal at the input of that block. That's not an issue, that's expected behavior.

There is a Level parameter in the Global EQ that you could use for that.

The setting that causes confusion is the ToggleExp setting in Global Settings > Footswitches > FS8 Function, set it to Stomp 8. ToggleExp is what "alternates from EXP1 to 2 with each pass of the ring and sleeve".

Try the stereo fx. From the Stomp's manual:

Yes, the Minotaur is a model of a Klon Centaur. "Treble" on the Klon suggests that it just adds treble but it's mids, too. So Line 6's "Tone" is probably a better name for that parameter. Think of it as a "everything except bass" level control after the distortion.

Both sound the same. AMP+CAB is convenient (one block only, can be saved and named as Favorite). Two blocks provide options (dual cabs, cab split to FOH etc).

The Euclidean Delay is made for a sequence of equally leveled repeats. Read the description of what Steps, Fill and Rotate do - once you get what it does you can create any repeating pattern. It can serve as the base in a parallel path that you can modulate with what you need.

Start with the Helix' full amp models (not preamps, no cab) using AMPED 1 as a neutral power amp (with VOICE set to FLAT and RESPONSE set to LINEAR).

Export the patch in question with HX Edit. Then attach it to a message in this thread.

Besides @rd2rk 's advice you could post the patch - I'd have a look at it.

True.

Maxed out DSP on the preset?

The switch is not directly compatible with the HX FX. That's why it's not listed as a compatible device. But you can probably use a hack to use the Toe Switch as a fake expression pedal with only two states (open / close) to switch stuff (EDIT: only momentary): For this the EX2's Toe Switch Out with HX FX's EXT 2 In. BUT: a 10k Ohm resistor needs to be added in parallel. This can be done by modding a TS cable where you open one plug and solder said resistor between tip and sleeve. Have fun!