This was confirmed to be a bug in the Pocket Casts TestFlight build I was using.

Resolved! But still mysterious.

I decided to try uninstalling and reinstalling every recently updated app on my phone, starting with my TestFlight apps. The first one I tried, Pocket Casts, doesn’t even have a Share Sheet extension, but after uninstalling it and rebooting my phone, my Share Sheet looks normal again! Reinstalling the Pocket Casts build did not reintroduce the problem.

I had definitely tried uninstalling and reinstalling several apps with Share Sheet extensions before to no avail, but this was the first TestFlight build I had tried uninstalling since the issue arose.

YMMV.

Mmm. The only thing on there left for me to try is to uninstall every recently-updated app I can think of with a Share Sheet extension. Will give it a try!

Good idea, but Content & Privacy Restrictions aren’t enabled.

If you’re on Gmail, buy Mimestream for Mac and never look back.

If you’re not using Google for your email, and/or you’re looking for something on iPhone then it’s a tougher choice. I wrote an extensive review of the options not too long ago and landed on Spark, but your priorities may be different from mine. Have a look and see what you think: https://kevinyank.com/posts/email-apps/

But you’re thinking hardware and not software? In that case, sounds like I need to book a visit to my local Apple Store.