With a parallel line level mixer you can keep your signal analog and just mix in some of the digital tone on top of it. Way more transparent. The downside is the complexity, and you can't use effects that require 100% signal like gate, eq, and tremolo. It is great for modulation, delay, and Reverb. This is how it was done in the 80s and 90s with all the classic rack units.
Yes, I have said online many times that I find the Fractal units remove punch and blur the low end. Many people always argue with me and say they don't hear it.
The problem with looking at rack units is they are all old at this point and don't have modern convenience like USB and computer editors. I have several of them, and they sound great, but I would question that starting today. However, something like an Intellifex has an analog mixer built in, so it sounds more transparent than something that digitizes the whole signal.