I guess ICANN's lookup tool (https://lookup.icann.org/) is probably more trustworthy than commercially operated ones; it would be a terrible look for them to engage in this practice.
But I always feel much safer using whois in a terminal than any website that can see what I'm searching for.
As a PSA to everyone, you should only ever use whois in a terminal window to see if a domain is available.
It's included with macOS, Windows (?), Linux or any other OS anyone's likely to use. [Edit: a reply says it's not included in Windows. It seems you can download it free here: https://docs.microsoft.com/en-us/sysinternals/downloads/whoi...]
I guess ICANN's lookup tool (https://lookup.icann.org/) is probably more trustworthy than commercially operated ones; it would be a terrible look for them to engage in this practice.
But I always feel much safer using whois in a terminal than any website that can see what I'm searching for.