not all of your listed symptoms match a failed clutch.
clatter at idle in any gear indicates DMF failure.
it can also explain the weird engagement / disengagement behavior.
another question before jumping to DSG clutch/mech failure, has the DSG service been done?
also, is the DSG tuned?
these DSG wet-clutches can last for a long long time, even when abused. i personally have >255k miles on my original clutch pack. >40k of that has been with a big turbo making 460nm of torque. more than 100k before THAT was on a stage 2 tune (ECU+DSG)
also worth mentioning: issues with engagement / disengagement dont spell out clutch issues if everything else checks out (tune + maintenance + DMF), it could be the mechatronics unit itself.
now, onto replacing the DSG clutch. comparing it to a manual will not fly here. you need a special DSG clutch placement tool to measure the backlash / play of the clutch pack with a machinist dial indicator.
once you get that measurement, you select the correct shim(washer) thickness to install with the clutchpack.
theres some youtube video's out there explaining this stuff.
if you dont want to deal with the whole adjustment procedure, you COULD just buy the friction / steel plates and open the clutch pack + replace the clutch material. this lets you just reuse the current clutch basket and therefore clutch shim(washer)
though i will note, this route has a much higher likelyhood of not working correctly since you may not install the new components correctly. with due diligence and taking your time, it should be feasible.