Sublime Text 4 dev builds (with public download links for Linux, Windows and Mac) are announced on their Discord [0]. If you're using Arch, or just want a quick download link to the probably most recent Linux build, see [1]. I believe a valid ST3 license is required.

[0] https://forum.sublimetext.com/t/sublime-text-discord-server/...

[1] https://aur.archlinux.org/packages/sublime-text-4-dev/