The Mustang critter that plugs into your guitar isn't bad but it does, more or less, sound like the modeller amp it's named for.
I've had a couple of MultiFX units in the past, I still have them (FX500/FX900/ZoomR16 & Roland Disclab 1), but none have decent crunch/distortion/fuzz and ALL need the fizz/top end rolled off.
I did have a nice, cheap VOXAC30 unit that plugged into my guitar...pre digital so analogue and circuit based. It sounded pretty good, albeit a little noisy. I "loaned" it to a friend.

For the tone you're after you should be using a ROCKMAN - the sound of Boston. They're out there in the ether, somewhere. Mind you outside a mix the Rockman can sound a little thin as it's made to "fit" and be EQd.
Oddly of late Rockman gear is being called the sound of the 80s but he was replicating/creating his sound of the 70s.

The couple of ampinabox pedals, (Joyo ACTONE is the best of mine), I do own & use are OK for draft work but I use them with some nice cab sims I acquired from a guitarist friend, (chap who only plays Gibsons & Mosrites into Marshall stacks with no fx and captured his own cabs - he's pretty cluey with tech but doesn't use it much in music making - he doesn't use his sims for anything but songwriting), and those cab sims EQ the pedals tones into something much more realistic. (I use Reaper so load ReaVerb and then load the cab into that via the file option followed by the -18dB option).
Most of the Spirit Level tracks I played rhythm guitar on were that pedal and cab sims.

Cheers
rayc
"What's so funny about peace, love & understanding?" - N.Lowe