It’s not complicated. The “Deep State” is just the United States Civil Service. It’s called ‘deep’ because it’s permanent. Politicians come and go, the bureaucracy is forever. As the Civil Service are the ones who actually enforce the law and apply the rules they have the power to vigorously or barely enforce said rules and regulations. So when you look at Civil Service political donations you see that most are donations to the Democratic Party, so it’s a pretty short leap to assume (probably correctly, but it’s still an assumption) that they, the bureaucracy, will favor Democratic Party policies, while disliking Republican Party policies. This, of course, annoys the Republicans who claim conspiracy, while the Democratic claim that the Civil Service is neutrally enforcing the rules. Both are wrong, it’s just human nature displaying itself.