Which champion should i buy?

Both can be in the jungle role

Kindred thrives in jungle and kites easily and fails in some lanes against certain matchups due to their squishy-ness. Ekko can also go jungle but does incredibly well in lane

It's more of a:

1. Jungling or
2. Laning

As far as which champion is just straight up busted? Ekko.... but play with what you like and what you're good at. I noticed you chose Ekko and Kindred which led me to believe you want to buy champions who are unbalanced.

Kindred plays similar to Vayne and Kalista. If you play other ADCs, you won't find anything new.