I know what is your concern!

You can just turn off Cloud in your router’s UI and then no day is send to the cloud at all.

I have told you what data is transferred and that is what it is. Nothing hiding! The router even keeps the logs there and every api call is recorded. I have stated in one above post of that will be enhanced so you can choose to wait until these features are available to use the cloud.

Anyway, do no need to use the cloud at all if you do not need to. You can even flash firmware from openwrt directly and problem solved.