Is there anywhere you can watch these old flash creations like Xiao Xiao and Homestar Runner with the original vector graphics? The reproductions I’ve seen on YouTube are terrible, in part because of the obvious video artifacts that don’t preserve the edges, but also because it loses all interactivity.

If you can grab a copy of the SWF somewhere, Ruffle[0] is a decent Flash replacement and compatibility is pretty good[1].

[0]: https://ruffle.rs/

[1]: https://ruffle.rs/compatibility

The versions linked to in the article use the original vector graphics. In fact I think they're the original post location (NewGrounds). From there you can follow the link to the author's page, which has them all:

https://zhu.newgrounds.com/

H*R is up again.

https://homestarrunner.com/main

Using Ruffle. Like the others, it's somewhat recent.

https://en.wikipedia.org/wiki/Homestar_Runner#cite_ref-18