My vote for OEM MAF as well or the wiring that connects to it. See if you can get a refund for the aftermarket and get one from peachparts or ********AZ

I'm dealing with misfires and hesitation on my 1995 E320 with ASR, but i'm waiting for BBA to take care of my Throttle Body, since that's an obvious cause.

If you want to see if your harness is good or bad, cut the outer isolation from the cable that goes to the MAF sensor. That's the hottest spot of the harmness since it sits right on top of the exhaust manifold.
The wiring to the MAF is the first to go bad.
If you see degraded isolation, than that's your issue. You can either replace just the leads to the MAF, if you're on a tight budget and pray that nothing else will short, or replace the complete harness. (Used ones with a newer build date can be found on CL or ebay) But brand new is the best option if you can afford it.
If your isolation is degraded, than your throttle body is most probably on it's way out.

The wiring isolation on this cars was made with the idea that it will disappear in 15 years. Shorted MAF, ETA ori O2 sensor can damage your ECU and that's something to keep in mind as well.
I had a bad coil that shorted the ECU, but luckily i was able to just restore the pin on the board of the ECU and it worked fine