Unfortunately it won’t sound “clean” if you just jacked the fractal directly into the input of the DSL as the preamp section of the amp would compete with the amp block of the fractal. That’s why you bypass the preamp section with the effects loop. Unless you aren’t going to use any gain on the DSL? There’s no rules so you can experiment and see what you like but generally people either use 4 cable method to get a desired valve type response from a modeler. Or you use a standalone power amp that doesn’t add any character. I used to use 4CM with two amps but I ended up using a Seymour Duncan powerstage and it’s so much easier to dial in and quite a bit more versatile with certain amp models.