I bought the Pro Edition because I thought it would also include a VSTi for Linux (VST3 is listed in Integration).
Unfortunately, no such plugin is included in the Linux archive (no .so file).
Is there already a plugin for Linux?
Or is there another method how I can synchronise the Pro Edition with my DAW (Reaper)?
Your best bet, ironically, is to use the Windows version via WINE. Then use yabridge (GitHub - robbert-vdh/yabridge: A modern and transparent way to use Windows VST2, VST3 and CLAP plugins on Linux) to create a bridged plugin file that can be run in native DAWs, in your (our) case, REAPER.
Using the Windows version for the time being also brings some more benefits - no odd crashes (1.8.1 Bug: Crashes when trying to activate Vocal Modes automation and 1.11.0b2 Linux Bug: Instant crashes with voicebanks installed), and Wayland support (by using WINE 9.0, and enable the experimental Wayland driver per instruction in this release notes: Wine 9.0 · wine / wine · GitLab)
EDIT: Unfortunately, no ARA2 support this way - yabridge doesn’t have ARA integration so the bridged plugin doesn’t expose ARA to the host - you can mitigate by using Reaper via WINE too but at that point I think we’d rather go back to Windows than going through such hoopa loopa haha