Not a lander but NASA has 2 potential Venus missions in their proposed Discovery missions! [0]
In regards to why not a lander: I would guess it's because it's not really necessary? Orbiters (like the proposed ones above) can gather all of the science that's really necessary to study a planet like Venus. Landers are useful to study more micro-scale science to, for example, search for life (see the Mars rovers/landers and the proposed Europa lander). And orbiters are significantly cheaper and easier to make. Landing on Mars is really really really hard! I can assume it would only be harder on Venus.
In regards to why not a lander: I would guess it's because it's not really necessary? Orbiters (like the proposed ones above) can gather all of the science that's really necessary to study a planet like Venus. Landers are useful to study more micro-scale science to, for example, search for life (see the Mars rovers/landers and the proposed Europa lander). And orbiters are significantly cheaper and easier to make. Landing on Mars is really really really hard! I can assume it would only be harder on Venus.
[0] https://www.nasa.gov/press-release/nasa-selects-four-possibl...