BRP069A81 worked with the daikin binding for a lot of people. the newer C-series boards (BRP069C4x etc) were often cloud-only with no useful local api, so the binding connected then sat there with dead channels.
if C81 really talks locally like the A81, try adding it as a normal daikin ac thing and hit the box on http:///common/basic_info from the oh host. if that returns json youre probably fine. if it 404s or only the onecta cloud path works, the binding wont do much until someone adds cloud support.
worth a try and report back what basic_info does. that answer usually settles it fast.
thank you for clarifying it. I have already this solution on upstairs, but on the ground level I can only put 3 units, no other options. Unfortunately I wait for someone can confirm (or not) the C81 can talk locally