Answering a question about adding launch icon on gnome panel. Actually gnome3 did not allow to do it by default. For alternative, you can add your list of favorites applications to be put on the panel by using Frippery Panel Favorites. It can be installed online from Shell Extensions page.
After installations you can view or hide it from Advanced Settings plug in that included in gnome3 desktop environment. There also some Shell Extensions that maybe will get your attention.
01. Shell Extensions page. https://extensions.gnome.org/extension/4/panel-favorites/
02. Advanced Settings included Frippery Panel Favorites. You can see it on the top panel.Share