[samhuk]

Passing by Venus is lowering the spacecraft's periapsis, increasing the orbit's eccentricity. The lower the satellite goes, the faster it will be at periapsis. Those speeds the GP comment is refering to are, in all likelihood, velocity as periapses.

[areoform]

Yes, indeed! It's the magnitude of its velocity around the sun at closest approach.

[cmpb]

There we go, thank you, that's the mental model I needed to bring it together