Or you are one of those whales at 200k+ power or you are in a new server. If is the latter, don't worry, as soon as your server hit its 60th day arena won't be anymore easy for you.

Then two more days. Servers go cross server the 1st day of the month after the server hit its 60th day.

Or maybe the issue is simply the level. You are too low leveled to meet somebody that can beat you. Once you hit 80-85 you will begin to meet 90-95s.

In ranked arena you cannot meet anybody that's 11+ levels higher or lower than you. So, currently, you are meeting only people in the level 65-85 range. This means you still are in the safety zone for your region (i am level 97, you won't meet me, for example, until you hit level 87 if you are in my region).

Paradoxically for you ranked arena is easier than training since in training there is no limitations.

P.S.: what lineup are you currently using? Just curious.