Comment by mg

In theory, Bluesky, Mastodon, Pixelfed etc could offer a service where you drag and drop the button onto the Bluesky/Mastodon/Pixelfed website where you are logged in and sign the reaction in your name. And send the post with a signed message like "Peter Prima endorsed this page with a thumbs up emoji /signed: Peter Prima"

This way, the web would get a decentralized like system.