The SNI extension is sent unencrypted as part of the ClientHello (first part of the TLS handshake). Any router along the way see the hostname that the client provides in the SNI data, and can/could drop the packet if they so choose.
On Apple devices, first-party applications get to circumvent LittleSnitch-like filtering. Presumably harder to hide this kind of activity on Linux, but then you need to have the expertise to be aware of the gaps. Docker still punches through your firewall configuration.
In fact, most web browsers are using DoH, so pihole is useless in that regard.
Although there are caveats -- if an app decides to use its own DNS server, sometimes secure DNS, you are still out of luck. I just recently discovered that Android webview may bypass whatever DNS your Wi-Fi points to.
For what it's worth, I do use Google products personally. But I won't go near Facebook, WhatsApp, or Instagram.
Please see hn guidelines: https://news.ycombinator.com/newsguidelines.html
Luckily for you (and many others) there is no requirement that points be coherent.
The Discord timeout occurred because anti-ads automod was triggered by crypto-related keywords. I saw the community moderator already explained.
I hope you can know the truth rather than be misled.
1. Try using pi-hole to block those particular endpoints via making DNS resolution fail; see if it still works if it can’t access the telemetry endpoints.
2. Their ridiculous tracking, disregard of the user preference to not send telemetry, and behavior on the Discord when you mentioned tracking says everything you need to know about the company. You cannot change them. If you don’t want to be tracked, then stay away from Bytedance.