I work for an internet service provider and I can confirm this ^^^. Wireless sucks guys. The stone cold hard reality is that copper wire is a more reliable way of transporting electrons from one location to the other, as opposed to radio waves. Error correction becomes very shaky when entering the realm of wireless, and that causes packets to appear on one end different than the other side, if the packet doesn't match, it's discarded and asked to re-transmit. If this happens more than a few times a second, then it is drastically noticeable in game. Wireless also introduces more protocol overhead and processing time for the data to get from one point to the next. I can't be more clear than tell you wired is always better than wireless.
Tldr just buy the $15 amazon basics adapter and you'll never regret the purchase. Just don't spend more than $20 or you are being sharked for the same performance increase.
Bonus: If you get bored of smash it works on all usb devices. You can give your slim laptop that doesn't have an ethernet port, huge performance upgrade, especially on upload and ping time for online games. Vroom vroom......