The rough numbers I can find are that the acid cloud layer is ~75km thick, which seems awfully long for any kind of tether that'll have to support its own weight. With the low pressure (~0.1 ATM) it'd also need to be a rather big balloon.
Further down, the ~100m/s (~220 mph) winds on the tether would likely try to drag everything sideways, scraping any probe across the landscape.
Acid's a solved problem; PTFE (Teflon) is a comprehensive solution to hot sulfuric acid, well validated in chemical engineering problems on Earth. It's versatile enough you can even coat balloons with it [0].
The hard part is keeping electronics cool. The balloon ideas offer a really elegant solution. You could cycle a balloon between altitudes—between the 500 °C surface, and cold layers of the high atmosphere, cooling off and refilling a thermal storage reservoir for the surface. On Venus, can find cool 20 °C air at a very reasonable, balloon-navigable, 0.5 bar pressure level [1].
Further down, the ~100m/s (~220 mph) winds on the tether would likely try to drag everything sideways, scraping any probe across the landscape.