Hello everyone!
A user has helped us in figuring out a workaround while we line up a more permanent fix.
Please download the insync-3.7.11.50381-fc28.x86_64 package and follow the workaround mentioned here (i.e., replace libxkbcommon.so.0 in /usr/lib/insync by a link to /usr/lib64/libxkbcommon.so.0).
Let me know how it goes!
Shoutout to Karsten for this!