A public beta for full support of macOS will be available in early Q4. For now, you can still double-click to open files in Finder. Everything else is working as usual.
The “full support” language is in regard to a change Apple made in macOS 12.3 that deprecated the type of kernel extensions used by both Dropbox, Microsoft OneDrive and others. This extension allowed Mac applications to open online-only files from Dropbox as if they were stored locally. For users running macOS 12.3 or later, a workaround is available, but the experience is less than ideal.
When this change was made earlier in the year, Dropbox announced a beta due out in March that would restore the functionality, but according to today’s news, that full public beta won’t be here until the final quarter of 2022.
…at which point macOS Ventura will be out.