As has been noted elsewhere, most dryers on the market can’t get anywhere near the 140℃ suggested for e.g. PPS-CF and PPA-CF. They’re also mostly garbage. I set out to design and build a better filament dryer, and believe I’ve succeeded. Check it out! I’ve done a very thorough writeup on my wiki, and both the firmware and models are available on Github. I’d love to hear your feedback and answer any questions!
I’m probably going to design a PCB to replace my crapnest of perfboards and wires; if there’s any interest, I could probably sell those, perhaps along with sacks of the necessary parts (you’d print the chassis).