Been tinkering with Wii emulation and found that most posts about how to access Dolphin's menu in game mode are too complex. So I decided to make a post about a simpler method I discovered.

[Assumptions] I'm using EmuDeck to set everything up and accessing the game through game mode. (Steam game Icons set up by Steam ROM manager).

[How To]

1. So first , go to the game's page and click on the "gear" icon. Then click on "properties".

2. In launch options, delete the -b in org.DolphinEmu.dolphin-emu -b -e (The -b prevents Dolphin's menu to be created in the first place)

3. Launch the game, then press the steam button. You will see a second window under the "Switch windows" section. Choose the second one, and you will see Dolphin's menu.

4. (Edit: There are better navigation solutions in the comments!) ~~In order to navigate it, change controller config to "Web Browser" preset~~
   Click on settings you wish to adjust. All the tabs you open in Dolphin menu will also show up under "Switch windows" too.

5. After you finish adjusting stuff. Simply close the tabs you opened and switch back to the tab that the game is on.

Hope this help people who stumble across this post!