Overclock Your Controller for Less Input Lag

By default, your controller adapter polls at a rate of 125 Hz, or every eight milliseconds. However, by overclocking it, we can increase that rate to nearly 10 times at 1,000 Hz. The result of this overclock, per the document by SSBM_Arte, results in “a much closer experience to console play. It considerably improves the latency stability, which directly impacts execution, and also reduces input lag.”
You might have seen this in action with a mouse.
Play Nintendo Switch Local and Online Multiplayer on Linux/Steam Deck – Guide

Emulation has come so far. To the point where you can actually play online multiplayer on PC and Steam Deck with Nintendo Switch games, thanks to the LDN version of Ryujinx. A number of benefits come with this, including:
no need to cough up $20/year for a Nintendo Switch Online membership higher resolutions than 720p/1080p higher framerates the ability to use controllers outside of joycons, pro controllers, etc. So let’s walk through the process of getting this set up.
Steam Deck: How Does it Melee?

One of the first things I wanted to do after getting my Steam Deck was test Super Smash Bros. Melee. Not just to see how well it performs, but also examine online play and see how the controls feel in my hands.
How to Get Melee/Slippi Working on Deck If you’re looking at getting online play set up on Linux, you can refer to the guide I wrote a few months back.
How to Use Smash Ultimate Mods with Ryujinx

As of Ryujinx version 1.1.112, users can now seamlessly load mods on Super Smash Bros. Ultimate with the use of ARCropolis/Skyline. Here’s how to do it.
Note: this tutorial is based off of the guide from GameBanana, but specifically tailored to Linux users.
TL:DR
Get yourself set up with emulating Switch games on Linux with this guide if you haven’t already Download Ryujinx and run it for the first time Download ARCropolis, extract zip to %RYU_DIR%/sdcard/ Download Skyline, extract to %RYU_DIR%/sdcard/atmosphere/contents/01006A800016E000/ Download any mod (plenty of them over on GameBanana), extract them to %RYU_DIR%/sdcard/ultimate/mods/ Launch the game.