I’m in the same boat with the COMPOSS.
This is what Virtual Fly’s official word is on the subject:
Is the COMPOSS compatible with MSFS2020?
We have been working on our Control Panel to bring COMPOSS to MSFS2020. It will be available to download from our website.
I emailed them a few weeks ago and they said they were working on it but couldn’t give me a date. If you want to email them, I’d love to hear what they say now. I’ve been such a pain to them recently that I don’t want to keep bothering them.