I have an Argon One m.2 case for my raspberry pi 4. The SSD is mounted underneath the pi on a circuit board. Unfortunately there's no ventilation for the SSD, and it was getting up to 90 degrees. I need to cool it down.

For now I've opened up the Argon one case, connected the Pi and the SSD board with a USB cable, and I have a small passive heatsink on the m.2 SSD. The top half of the case with the Pi is upside down otherwise the pi circuit board would be on the shelf directly. The SSD dropped from 90C to 45C, and the Pi temperature dropped from 45C to 32C. There's no physical protection for either the Pi or the SSD right now, which isn't ideal.

I considered buying a new m.2 enclosure and putting the SSD into that. Unfortunately all the enclosures I can find that are reasonably priced seem sub-optimal from a cooling point of view. To get a good m.2 enclosure they tend to be US$100. This case doesn't seem too bad, but it's another NZ$55 or so and I don't want to spend more money on the R.Pi. My next computer for Home Assistant and such will be a mini PC with a better case and good cooling.

I'd like to take the SSD and it's small circuit board out of the Argon case so I put the Argon case back together to protect the Pi. I'd then want to put the existing SSD and circuit board into another case. I can probably find a case at PBTech or Jaycar, but I'm not sure how to mount it into the case firmly so it doesn't move around. The USB port is anchored to the circuit board, the case just has a hold to allow insertion. Any suggestions how I would mount this circuit board to a new case?

Circuit board is approx 104 x 96mm.