Moslty everything you need to know about OvO's services is covered here and in the TOS.
This one is easy;
This is explained on the homepage and in the TOS. Please read [this].
At the checkout, you can choose to install any OS from OvO's library (Arch Linux requires a manual SSH setup).
All VPS servers are provisioned automatically within 15 minutes after payment confirmation. Dedicated servers are delivered within 48 hours, though in rare cases, it may take longer.
The servers are using AMD EPYC 7702 series processor.
Yep, every linux VPS & dedicated server comes with root permissions. (Recommended) Change the root password when you receive the server.
Yes, this is allowed. But in that case open a ticket, so abuse is handled accordingly.
Yepper! Create a ticket, specify the specs you'd like to upgrade, wait for a response, and voilà! :) (The price will be updated accordingly based on the spec requirements.)