I’m having similar issues ( A350 not detecting modules ), has your a350 continued to work/detect all your modules after downgrading and upgrading the firmware?
Based on your comment here I am attempting to downgrade to 1.18.2, then back up to 1.20.3.
I feel a little crazy though trying to get this thing working/having no clear viability into why it is not behaving.
One follow up question, what modules did you have installed when you downgraded and upgraded in case that is a factor.