Yes but damage seems to be done. Distros are talking or have moved off of it to zstd.
There are some, probably. But any exodus will be slow. Xz isn’t useless because it was dangerous once.
Zstd and xz fullfil different needs. Xz take more time to compress and is faster to decompress as far as I know.
XZ is a slog to compress and decompress but compresses a bit smaller than zstd.
zstd is quite quick to compress, very quick to decompress, scales to many cores (vanilla xz is single-core only) and scales a lot further in the quicker end of the compression speed <-> file size trade-off spectrum while using the same format.