How can we maximize the expected number of runs in a shuffled deck of cards?

Take a standard deck of cards, with 52 cards, 26 red and 26 black. A run is a maximum contiguous block of cards, which has the same color.

So,(𝑅,𝐵,𝑅,𝐵,...,𝑅,𝐵) has 52 runs.(𝑅,𝑅,𝑅,...,𝑅,𝐵,𝐵,𝐵,...,𝐵) has 2 runs.What is the expected number of runs, $E_{run}$ in a shuffled deck of cards?

We know that the answer to this question is 27. Source: What is the expected number of runs of same color in a standard deck of cards?

But what if we don't have 26 red and 26 black? So:

Suppose we have $x$ red and $y$ black cards, where $x+y=52.$ Prove or disprove the following:

$E_{run}$ is maximized when $x=y=26$. If not, find the pair $(x,y)$ that maximizes $E_{run}$ and find max($E_{run})$.

My concern for this problem is that $E_{run}$ may become too computationally complex to calculate when $x \neq y$. Does anybody have a general way to find it?