this is the truth. even not daisychaining power, some pedals will be noisy without a specific kind of isolated power supply that cuts off the power which comes out of the wall before it goes back through the cable to complete the power circuit.
Chaining effects pedals for audio and getting an optimal result is about the order in which the effects are chained - usually high gain effects, pre amp, compression, stuff like that comes right after the source - where modulation or space inducing effects like reverb or delay would come near the end. there is a lot of info on youtube etc about the “best” order to chain pedals but honestly your ears are the best judge of that. also with synths, pedal behavior is inconsistent so what works with one, might not work with the next. pedal audio will not degrade just because you chain it, but putting a high gain effect at the end of the signal chain or something like that might, so theres more to consider. the mixer is helpful if you want like, the same reverb on more than one channel and you have several inputs and you want to run it through an insert and back in the same way to use it on the aux channel. but you’re talking about one synth, just play around until you’re happy but if you use any fuzz or overdrive, put it first in line after the synth.
I suppose the other helpful thing about using an aux send on a mixer is if you want a dry signal, you don’t have to tap off all the pedals, just turn down the channel volume. If you run the pedals direct in line and want a dry signal, have to turn them all off. but this is just nitpicking.
