Possible flywheel failure

This is my first post in a forum ever I am pretty sure, so I apologize if this is not the right thread.

I have a 2013 S5 Cabriolet (75K miles), automatic trans which is the s tronic 7 speed I’m pretty positive. My problem is when I have the car in reverse and I let of the brake to fully engage the clutch, there is definitely a rattle. Some things I have read refer to nails in a can, and this is the sound. It has gotten worse over the last two months since I first noticed it. I believe it is starting to happen when engaging forward gear but barely noticeable. Definitely not making the sound in neutral, it’s only in reverse after taking my foot off the brake and the DSG clutch fully engages. I ran calibration through VCDS, all went well. The car does not like to shift into first when slowing also, I find I have to completely stop for it to shift down by itself. Otherwise I end up accelerating in second gear through red lights or corners where I only slow down almost to a stop.

My question is, does this sound like the duel mass flywheel, does this car even have a duel flywheel? I’m not a trans guy really, but how could one possibly narrow down a bad dual flywheel, and the million dollar question is would I have to pull the engine to get to the flywheel?
Any help at all is greatly appreciated! Thank everyone for this awesome group regardless.