In OGS, you have to use 2 dropdown menus to select a rank range to which you want to restrict your game challenges.
I find this a bit cumbersome: you have to remember your current ranking for a particular board size, you have to be careful not to switch the order of the upper/lower bound, you have to click and search twice, etc.
Most people want to use this feature to get an opponent around their current ranking (with a possible preference of slightly below or slightly above their rank).
I think a solution like lichess has is much more intuitive:
EDIT: Didn’t realise the automatch has something similar, but still, it could use some re-design. My suggestion: Restrict rank based on interval around your current rank - #10 by jmont