One cool trick is to learn about a TDL is to visit nic.TLD to get info about the domain, for example https://nic.sharp/
Because I've found some that don't have it, like https://nic.amazon
For that amazon link, I think the underlying website is just flakey. I was able to get the page to load once, here is an archive link of it working https://web.archive.org/web/20230616013716/https://nic.amazo...
Some examples: https://whois.nic.sharp http://whois.nic.amazon https://whois.nic.horse https://whois.nic.google https://whois.nic.trust
See the gTLD guidebook here: https://newgtlds.icann.org/sites/default/files/guidebook-ful...
Section 4.1 on page 268 of the PDF covers whois.nic.$GTLD
Country codes can basically do whatever they want.