Trump's style of corruption isn't conspiracies in dark alleyways. It's a public brand that is understood to be shameless and sleazy, protected by a thin film of mafia style plausible deniability. Here's an explanation for Ratcliffe being subserviant to Kremlin interests that doesn't involve any subterfuge or secret meetings.
Trump doesn't hatch elaborate plans and instruct his minions to carry them out. He's much too stupid for that, and, frankly, in a weird way, he's also too smart for that, because he doesn't need to hatch risky plans that could land him in trouble if he were ratted out. By simply raging at the hint of any idea he wants his administration to steer clear of, and encouraging anyone who puts up distractions away from those verboten topics, he establishes a culture where everyone is complicit in his criminal activity, but appears from the outside to be acting more or less autonomously.
Let's start with the premise that Ratcliffe, like all yes-men who Trump surrounds himself with, is a chicken shit stooge. Ratcliffe, being a chicken shit stooge, is therefore inclined to ignore or downplay Russia on his own volition because that's the path of least resistance in this administration. He also knows he gets brownie points for deflecting any intelligence about election interference (a topic that always seems to hover around Russia) towards any other nation.
It doesn't take a massive, elaborate conspiracy here for it to be plausible that Ratcliffe's actions are indirectly yet strongly influenced by the Kremlin.