I installed Big Sur and migrated applications & settings, but not user accounts, from my boot up drive (MacOS 10.15.6) to Big Sur. I am surprised by how much of my software works. InDesign CC 2018 no, InDesign CC 2019 & 2020 yes. Canvas X Draw no. But most importantly, Indigo yes.
Without doing anything the Indigo schedule worked fine and the Indigo iOS app which is on iOS Public Beta 4 also worked fine. No problems, no need for me to do any work. I think I had to re-enter the Indigo serial number but it was moved to a new drive.
I am a rather simple user of Indigo so I cannot comment on plug-ins. I use Insteon and on X-10 device so there is room for some hardware to not work. And all I use are lights. So the obvious stuff has been working for me.