The only way a suppressor can make your gun inaccurate is if you dont screw it on properly/tightly enough causes it to be crooked which causes the bb's to hit the outer edge of the hole. Or you get a manufacture defect in yours making it crooked out of the box.
There actually are suppressor bottles for the airsoft market, if anyone recalls madbull came out with the pop bottle suppressor/loudener it screwed onto any 14mm thread and on the end of it you screwed on your pop bottle. either you drilled a tiny hole in the end for the bb to pass through or you cut the bottle in half making it an amplifier.
Like stated before there's no way for you to have a separate barrel in the suppressor the best you can do is for example a M4 if you have one of those 2 piece outer barrels, so if want a CQB platform but with a suppressor on you can do that. Atleast the inner barrel is passing through the suppressor but if you want to take off the suppressor you can screw back on the barrel extension making it a full length M4. Either option is the same thing just one has a suppressor and one doesn't
Here's an example with my old SCAR
Inner Barrel
Inner Barrel being hidden with outer Barrel Extension
Inner Barrel hidden by suppressor (no barrel extension)
Inner Barrel hidden by barrel extension and suppressor (mind you the inner barrel ends at the flashhider)
This is the best you can do, unless you got a super computer that can align everything to the .00000001 of a mm then yeah it'd probably work.