The plugin adds a page under Settings > Payloadless with three groups of switches. Each one is independent and takes effect as soon as the settings are saved.
Front end: disable emojis, disable embeds, clean up the head, remove jQuery Migrate, remove Dashicons for visitors, remove block library CSS on classic themes, remove the password strength meter, disable RSS feeds.
Editor and admin: Heartbeat API mode and interval, autosave interval, post revisions to keep, disable remote block patterns.
Background: disable self-pingbacks, disable core XML sitemaps.
Only the safe switches are on by default: emojis, embeds, head clean-up and self-pingbacks. Everything else is off until you turn it on.
The plugin contacts no external service and sends nothing anywhere.
Screenshots
The front end switches: emojis, embeds, head links, jQuery Migrate, Dashicons, block library CSS, the password strength meter and RSS feeds.
Editor, admin and background switches: Heartbeat, autosave and revision intervals, remote block patterns, self-pingbacks and core sitemaps.