That’s not strictly true.
There is the option to play with or without handicaps.
IF handicaps are selected, then the lower ranked player gets the handicap stones AND the game is ranked as if it is EVEN. Each player will get the same amount of rating points for winning.
IF handicaps are NOT selected, then the game is ranked as if it is not even: if the lower ranked player wins against their more skilled opponent they get a lot of rating points, wheras if the higher ranked player wins against the less skilled person, they get hardly any rating points.
For some reason, at OGS not-handicapped is the default (unlike some other servers). I don’t know why that is - having less handicapped games played reduces the basis for the one-rank-per-stone expectation.