It is highly recommended to show your inputs either by an external program such as:

m-overlay, univrsal/input-overlay, gamepadviewer, or Dolphin's built-in input viewer.

Recommended Input Display

m-overlay

This program directly hooks into Dolphin and reads the game memory looking for inputs. BlazinZzetti added support for Shadow the Hedgehog.

OBS Configuration Guide (See the sidebar for Linux and other steps):

https://github.com/bkacjios/m-overlay/wiki/OBS-Setup---Windows

Works for both Windows and Linux, and reads the input directly from the game.

For Linux you need to take some extra steps:

1. Install lua51, lua51-sec, and run setcap for your love binary. https://github.com/bkacjios/m-overlay/wiki/Linux

2. You will need to manually Chroma-key the Window in OBS Filters, as the Transparency option is only available on Windows

Alternative Input Display

Gamepad Viewer

Recommended for Windows, but usable anywhere with embedded Browser capture support

Generate a customized look from the options available at:

https://gamepadviewer.com/

Add a Browser Source in OBS and add the generated URL. Ex https://app.gpv.gg/?p=1 would give you an Xbox controller using controller 1.

Univrsal/input-overlay

Requires using OBS Studio for recording.

Recommended for Linux. Compatible with native and flatpak versions of OBS Studio.

Available as .deb and in the AUR. dreamsyntax uses input-overlay-bin from the AUR.

https://github.com/univrsal/input-overlay/wiki/Installation

This OBS plugin is added as a new source type in OBS Studio

You will need to specify an Overlay image and config file. By default, they are installed to /usr/share/obs/obs-plugins/input-overlay/presets/. Alternatively, you can download the presets from the main github link and store them elsewhere.

Choose your Gamepad in the id list, and you should be all set.

Dolphin built-in input viewer

In Dolphin, under Menu bar -> Movie, select "Show Input Display".

Be sure that under Config -> Interface, "Show On-Screen Display Messages" is enabled.