Let's say we have input data X and a hashing algorithm H that produces 256-bits of output (e.g. SHA256).

Now, let's take a second hash function G that produces 128 or more bits of output (say RIPEMD128 or SHA1). If we define our final hash function L := sub128(H(q)) + sub128(G(q)), where sub128 takes first 128 bits of the result and + is concat, so that the result is 256 bits again.

Is it now more, less, or about the same difficulty to Y such that L(X) = L(Y) compared to how difficult it is to find Y such that H(X) = H(Y)?