How can I disable this new Collection-feature (i.e. ignore MergeID) and let JD2 list all found downloads of all enabled variants in the LinkGrabber without creating a new Collection for every single wanted variant?

EDIT:
Could it be that using more than one itag[*] at the same time is not working?
Whichever is the first in the name-pattern is being replaced properly, but the next aren't.

This would need a conditional flag for itag[audioid] and itag[audio] when a non-DASH-variant is being named, as only DASH-variants have two itags. Otherwise the plain string "itag[audioid]" (or "itag[videoid]", whichever is second) is added to the filename.

EDIT2:
Why is JD2 preferring the non-DASH-variants 360p-streams (18), although higher quality DASH-variant (135) is available? DASH-audio (134) is also better (128kbit/s) than the audio in the non-DASH-variant (96kbit/s).

Example: **External links are only visible to Support Staff****External links are only visible to Support Staff** with a collection for 360p-variants and "Best mp4" disabled.

EDIT2.5:
Toggling DoExtendedAudioBitrateLookupEnabled and JD2 uses the DASH-variant for the 360p-quality for the link above instead of the non-DASH-variant.
Maybe this option can be exposed in the Youtube-plugin-settings?
Here's an example for a video where 360p is the best quality: **External links are only visible to Support Staff****External links are only visible to Support Staff**

EDIT3:
Downloading DASH-variants:
Using JD2 (up to date): 70kByte/s
Using a JD2-backup from March 31: >6000kByte/s
Youtube-DL: 6858kByte/s

Non-DASH-variants are as fast as ever.