The Space Exploration SE question Premature detonation of explosive bolts when landing on hot Venus? explains the need for and widespread use of pyrotechnic fasteners and cable cutters for Mars landers and elsewhere in spaceflight, and points out that Venus' atmosphere is already 75 °C and 1 atmosphere at an altitude of 50 km and roughly 500 °C and a dense 90 bar supercritical fluid at the surface.
So anything on the outside of a lander is going to get hot during the long descent to the surface in this thick soup.
Questions: What are the chemical and physical constrains on reliable, easily to electrically detonate explosives for pyrotechnic devices that will prevent them from spontaneously detonating at 500 °C when landing on Venus? Are there any realistic, potential candidates?
For example; do we need reactions that are less exothermic? Or a higher barrier between initial and final states? Or a lower density so that below some critical temperature an occasional molecule "exploding" doesn't trigger the next one so easily?
These examples are on Mars, not Venus. Click for larger
left: From How were Perseverance's cables "cut" after touching down? in Space Exploration SE right from this answer there. source: NASA/JPL-Caltech and source: NASA/JPL-Caltech