Find Twitter Hashtags
Although Apple pulled its direct Facebook and Twitter integration out of macOS and iOS a few years ago, the ability to search Twitter is still available in Spotlight.
This works best with hashtags, although tweets matching normal searches will sometimes show up too. Simply call up Spotlight, type in what you want to find, and a “Twitter” section should show results from the social media service.
On iOS and iPadOS you can tap-and-hold or tap through to see the full tweet or open it in the Twitter app. On macOS, everything is shown in the standard right-side preview panel, with a link to open the result, which will open in the official Twitter app for macOS if you have it installed, or simply to a Safari web page otherwise.