Since its October update, the Dash to Panel GNOME Shell Extension supports vertical panel orientation.
You also need the GNOME Shell integration browser extension installed. You can install it for Firefox or for Chrome, depending on your choice of web browser.
Additionally, install Tweaks to access the extension's options (and a bunch of other useful GNOME settings):
sudo apt install gnome-tweaks
Now, you can visit the Dash to Panel GNOME Shell Extension webpage, toggle the switch on the right-hand side of the page to ON and click Install on the pop-up.
Then, press Alt+F2, input r
and press Enter to restart GNOME Shell to make the extension take effect.
- To enable the vertical panel: open Tweaks → Extensions → click the cog icon next to Dash to Panel → set Panel screen position to Left or Right.