It's not that simple. Mercury also has a magnetic field. Which is a real head-scratcher, as it's even smaller than Mars.
Internal planetary dynamics are complicated. To get a dynamo you need fluid flow. But whether something is liquid or solid depends on both temperature and pressure - temperature increasing melt, pressure decreasing it. So there's a very complicated interplay.
Uber has long proven themselves to be eminently trustworthy and never scheming up shady ways to try to drive their competition out of business, so we can just take them at their word on this.
Very little energy reaches the Venusian surface - Venus's albedo is twice that of Earth's, so most light gets reflected from the cloud deck, and what does enter gets quickly absorbed in the clouds and thick atmosphere. Also, the crust is not what drives a dynamo, the core does. Nuclear decay is what drives terrestrial planet cores, not solar input.
Also I don't know what you mean by "rapid crust recycling", unless you mean Venus's global resurfacing events. But those only happen once every several hundred million years. And they take about 100 million years to complete, they're not rapid.
To downgrade the human mind is bad theology. - C. K. Chesterton