What is the difference between WideGuard, WideGuard (TCP), OpenVPN (UDP), OpenVPN (TCP) and IKEv2?

I know that Stealth is the best protocol available but I just wanted to know what’s the difference between the remaining protocols.

Stealth is not the “best” protocol available, it is just a Wireguard connection wrapped in a special TLS packet that allows it to not be easily-recognized.
Besides that, all theses protocols are open-source and you can find the information that mean something to you easily. But otherwise, just use the protocol that work the best for you.

Stealth is not the best protocol.
Due to the obfsucation and use of TCP it generally is slower than Wireguard UDP and consumes more energy due to higher CPU load.
You should not use it as long as you are not in a country which censors VPN usage. You also won’t really hide the VPN usage as all your traffic goes to a single IP in a datacenter nonetheless which makes it pretty obvious.

You should simply activate Smart protocol which will choose Wireguard UDP by default as it is simply the quickest.

You’ve already gotten sufficient answers but I will chime in that I only use IKEv2 as it is set up as a separate vpn connection on iOS and allows me to use DNSCloak or lockdown for dns filtering at the same time.

Why choose Smart Protocol if you knew it just default to Wireguard UDP which you also knew it’s the fastest?

Pretty good answer. I actually create my own VPN which makes my internet life faster

Because Smart will automatically switch to Stealth or Wireguard TCP if the connection you are connected too blocks Wireguard UDP or VPN traffic.
Then you don’t need to hassle with manually switching, smart will do it automatically.

Hmm, I see. Seem I prefer to do it Manually. With that, it can inform me that someone, somebody, something block my current choice. That the part I more interested to investigates.