From @mosseri on Threads:
Hidden 💎 if you long press the share button on a thread it’ll pull up the OS share sheet instead of the Threads one in case you want to get there quicker.
If you’re trying to use the Share Sheet to capture Threads posts, you’ll find yourself clicking the Share icon, then “Share via…” every time – instead, you can long-press on the icon and the native Share Sheet will pop up again with your shortcuts ready to go.
Fun fact: I helped get this same functionality implemented in the Twitter app back in 2020 after mentioning how important it is for Shortcuts users – shoutout to fellow Shortcuts creator Robert Peterson for emphasizing my point in the, ahem, “thread.”