Are you talking about losing resolution when you are using an HDMI switch or are you saying your Nintendo switch looks worse when it is docked?

Maybe your switch only supports lower resolutions. For example your TV might support 4K but your switch only supports 1080p or something.

No a hdmi switch not Nintendo Switch

Its says 1080p on the device

Is that the resolution you normally play at when you're not using the switch?

How do i check that

It’s likely a low-quality switch if it works fine without it. Double check to see if it is recommending a lower resolution on your PC. ‘Pixelated’ issues are resolution or anti aliasing related.

What console are you using?

I use it on my tv Ps3 Wiiu Ps4

Ps3 ps4 wiiu

Which ones look blurry? PS3 and Wii U only support up to 1080p anyway, so I would expect them to look fine on your HDMI switch. Maybe it's just a low quality switch?

Anyways on all three consoles you can go to the system display settings menu to verify the resolution.

I only checked my wiiu yesterday it was on the game mario kart

I will check what the device says

What are you guys using for multiply consoles ?

Multiple HDMI cords, I try to avoid switches because you can lose some fidelity with the cheaper ones.

Best thing you can get is a short, gold plated HDMI cable (shorter has lower latency because the signal doesn't have to travel as far, and gold plated is a superior conductor. Gold will also resist oxidation/tarnishing).

If your TV only has one HDMI port then leave the TV port plugged in and plug the other end into the console you're currently using.

Is the issue only with that set of cables?

Short like 1m

Even shorter. The one for my PC is only a foot or so because my monitor is close to my tower