How should I unlock champs?

So I have 7k ish BE with only Ahri unlocked. I could either spend it all on Kindred or buy a ton of low costs to get ranked quicker. Which should I do? Edit: changed IP to BE, imagine I changed the poll.
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We're testing a new feature that gives the option to view discussion comments in chronological order. Some testers have pointed out situations in which they feel a linear view could be helpful, so we'd like see how you guys make use of it.

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