> In Russian, there's an expression "like a saddle on a cow", I'm not sure what the equivalent in English would be

“To fit a square peg into a round hole”

Close but not the same. In Russian, the expression implies an "upgrade", a failed attempt at improving something that either doesn't require improvement or cannot be improved in this particular way. This would be a typical example of how it's used: "I'm going to be a welder, I need this bachelor's degree like a saddle on a cow!".