What is Riots method for measuring success in terms of balance?

I am genuinely curious. Is there a clearly defined goal that they are striving towards, or are just just content to nerf/buff BOTRK 2 times a season every season for the rest of the games life?

What numbers or statistics are they trying to reach in terms of champion popularity, ban rates, and win rates?

Do they have numbers for generalist champions they are trying to achieve, with other numbers for niche and counter pick type champions?

I feel like they just spin words when they talk about changes. In the last 3 years, I have seen no clear indication of what hey are trying to actually accomplish with so many patches so often.

Do THEY even know?