Is it possible to see your ping?
Sometimes, it seems that I'm desynced with the server.
Things like I'll be hit by things that clearly were going next to me or picking up an egg half a second after touching it.
I would guess I have a high ping, but I don't seem to have a way to check.
So is there a way to check the ping in Splatoon 2?
Sadly, no. Plus, there's no dedicated server associated with Splatoon 2 (this game uses P2P connection), so that means your ping value will vary depending on the host.
However, there's something you can do:
Buy a Switch dock for OLED version ( https://www.nintendo.com/store/products/dock-oled-model-black-116470/ , https://www.nintendo.com/store/products/dock-oled-model-white-116471/ ). This allows you to connect with LAN cable, so if you have unused LAN cable around you, this is where you'd use it.
Place your Switch near the Wi-fi router (if it already isn't). Many things can interrupt Wi-fi radio wave, resulting in packet loss and lower speeds.