Every generation of CPU has high-power and low-power variants. The i9 is a high power variant that generates a lot of heat but what you want is the low power variant.

I recommend looking for a used laptop with a Core Ultra 7 165U (<$500) or a Core Ultra 7 268V (>$1000). Maybe an HP EliteBook. Either one would be faster than your old i9 and run much cooler.

Case temperature is very much at the discretion of the laptop OEM. Some OEMs take regulatory limits on skin temperature seriously and ship a well-tuned thermal control system that keeps the case at a comfortable temperature. Others push close to the legal limits to keep fan noise in check. Others ship plastic enclosures so they can get away with even higher temperatures (since plastic has lower thermal conductivity than metal, and thus a harder time cooking your thighs) at the expense of more noise.

The StarFighter has a metal case, so when running at high power levels (45W sustained according to the spec sheet) it will either get uncomfortably hot somewhere on the case or at least a bit noisy from the fans, but since it's a bit thicker than the 2019 MacBook Pro it should be able to cool itself more effectively. But when running at the performance level you're used to the power draw should be plenty low enough to make temperature and fan noise not a problem: roughly double the peak CPU performance means you can turn down the power limits a lot and still have a better-performing machine.