Hello, if you weren't already aware, a mod that swaps the gamepad and TV screens has existed for quite some time now. I think it was made to enable Splatoon to be played with just the gamepad. But since it's open-source, I went ahead and slightly modified the source code to make it so the gamepad screen is put onto the TV but the TV screen is not put onto the gamepad (the audio still swaps, however). This means if you have an HDMI capture card you can effectively record the gamepad screen while still playing on the gamepad.
Original mod: https://github.com/OatmealDome/SwapDRC/releases/tag/1.3.1
Updated mod: https://drive.google.com/drive/folders/1WCPonfZXtfqEGtAXtKWVBu1NyQrijlAP?usp=sharing
Using this mod during games like Metroid Blast enables you to record the Gunship's perspective, which is nice. Using the mod during Fruit Cart is basically cheating, though. As such, for speedruns submitted here, swapping screens is only allowed for team games and is not allowed during solo games. It is ok if the mod is active while playing solo games, but you may not swap the screens.