You don’t. The Control tab in PaperUI only shows Channels from Things that have been linked to Items.
MQTT us a 1.x version binding. Therefore no Things and no Channels and no Links. This they never already in the Control tab of PaperUI.
PaperUI is intended for adminstration and configuration, not day-to-day use of your home automation. For that you should create a Sitemap and user BasicUI, or use HABPanel. In either option all Items regardless of what they may be bound to or linked to can be displayed and controlled in the way(s) you want.
Habpanel is completely built in the browser. Only BasicUI and ClassicUI require text based files.
However, be aware that the iOS and Android OH apps only work with the text based .sitemap files. If you plan on using those apps you will need to create text based configs for the UI.
Though HABPanel can be used on a phone’s browser as well.
Well then…
Homekit on my iPhone and iPad
HABPanel in a browser.
I have the best of all worlds, especially since the Apple Home App is not available in a browser