That 21 days may be a glitch. Some sellers with 1 or 2 day handling times have been seeing crazy extended times in their listings (and other viewers are seeing it too)
I checked a few of your listings: 2 showed Mon 6/18 (the economy shipping ones) and one showed Sat 6/16 (FCM one). I'm in Sacramento, so I'd guess you have maybe a 2 day handling time.
The handling time is a per listing thing. You need to go into each listing and check and revise it there. If you are using the Quick listing form that option may not be present. On the Advanced listing for it's about 3/4 of the way down the page in the Shipping details section.
Alternatively, you can bulk edit all your listings at once if you plan to use the same handling time on all of them (or edit in groups with different handling times). I'd check a few manually first to see what's going on to cause that 21 day time you see first though.
If using seller hub, can't help you - things may be different.
