Just an FYI, Ayane's 6K2K is actually a good string, it's just so abusive online due to crouching registering so late in latency. Also gets misused as an opening string too often (gets blown up offline that way easily), when that's not it's purpose.
Lately I've theory'd 6K2K as a pressure resort, and in recent sets, has proven to be so for me.
6K is +15 on neutral hit, 6K2K is +18 on neutral hit (used to be +23 and honestly I now understand why it was changed to +18). 6K itself opens doors to threshold for i10 to i13 strikes (this is how I've always utilized the 6K). 6K2K opens doors for i10 to i15 strikes. If you're to use to this as an opening, use it sparingly because it's not difficult at all to counter hit the delay into the low, and it is not difficult at all to block 6K2K straight up without delay.
If someone actually tries staggering out of 6K, the low hits them and puts them back into the situation for them staying on defense. If they low hold (or low hold out of stun) expecting the low, they get smacked by a mid or low thrown. This is how you correctly condition someone.
(The online tactic in this, and one that I really hate seeing, is that people try to condition you to block the low and low throw you for it because you have to guess and cannot just react on read since crouching takes longer to register. Offline, this will not happen, either you block it or retaliate at the delay/free cancel.)
6K > 6K is a knockdown, so that 6K can be a 6K2K for knockdown, giving you easy (and auto-pilot) access to the 66K (66KK4) unholdable on players who like to tech up.
6K and 6K2K for offensive pressure can keep opponents at a stand still because it trips them up (same for 3PK but is slower).
If someone staggers my 6K, I'm left at frame advantage regardless and can utilize strikes that are at i16 frames, or go BT for block pressure. I have other forms of utilizing 6K2K from certain juggles and other bits but that's my own thing since I'm switching up my repertoire anyway.
Just putting it out there that 6K2K is legimitely fine, just works best as pressure, not a go to opening string.