No, definitely not, that Plasma 6 is in alpha phase means that it is not yet ready for production, and is meant for being use specifically inside a virtual machine. The same in Arch and any other rolling release distro.
Arch might package it for their KDE-Unstable repo though. But that is also a repo people have to manually add to get it.
With good reason! Plasma 6 is not yet ready for general purpose usage in any shape or form.
No. Maybe a project repo will have the alpha version, to start the work into packaging Plasma 6, but it will not reach Tumbleweed itself.
I've tried it in a VM and it was very buggy, so, I doubt it would reach any distro in this stage anytime soon
KDE
KDE is an international technology team creating user-friendly free and open source software for desktop and portable computing. KDE’s software runs on GNU/Linux, BSD and other operating systems, including Windows.
Plasma 6 Bugs
If you encounter a bug, proceed to https://bugs.kde.org, check whether it has been reported.
If it hasn't, report it yourself.
PLEASE THINK CAREFULLY BEFORE POSTING HERE.
Developers do not look for reports on social media, so they will not see it and all it does is clutter up the feed.