Reading the github thread points to a case of: "My country's governemt mandated it's ISPs fuck with my internet traffic, but steam P2P stuff used to not be affected but now is" across mutiple countries. People have found it works again if they roll back some of steam's dlls so Valve can probably fix ir.
IMHO, issues with formating, like the ones you describe, should be cought by a linter. Or even better yet, enforce format-on-save in all editors your team uses and have it automatically re-indent and reformat the code so what indentation it was originally indented with irrelevant.
I think this approach would work, but I tend to work on files < 10k LoC, it might get annoyingly slow past that.
Brendan Eich was making a point about the tab key also being used to switch to different text fields and buttons. This makes it difficult to type in certain applications. A space doesn't have that issue.
About your point of tab being represented different on different systems: It will always be ascii 9, how it's draw does differ between text editors but I consider that one of it's strengths for programming. Everyone can configure what an indent looks like for them, it makes reading code easier.
Blocking dns leaks from the local network will not prevent sentry from sending them to the cloud. Blocking sentry from reaching the cloud (like said in the post) will.