Here's one for $20 complete with 40A SSR (solid state relay) and heat sink, plus a spare type K probe (not suitable for your salt bath, as it has a 400°C limit so it would be relegated to other things, but it will work with your salt bath thermocouple).
FWIW these controllers are fine but the SSR rated 40a is actually a 16a device internally. I saw a vid (https://www.youtube.com/watch?v=DxEhxjvifyY look at about 2:30 he tore down a "25A" which had a 12A rated SCR) about this and tore down A 40A I had bought and confirmed it. Most cheap chinese sourced items are counterfeits in some way like lithium batteries that are simply relabeled under capacity batteries.
Case heads have to be hard, as this increases their tensile strength. If they are soft, rifle pressures inflate them like putty and they can blow out under pressure. When they do, this rapidly escaping high-pressure gas will normally split a rifle stock and often damages the bolt face and wrecks the magazine under the receiver into the bargain. For this reason, ovens are never used to anneal finished cartridge cases.On the subject of annealing, what is the danger of letting the brass get too hot?