That's good to know. So it was hot with c-lightning or lnd? And did you then use an external SSD or how did you manage the storage?
I was running LND on the Pi. I don't think it matters; It would have been hot with c-lightning as well. I don't remember how much CPU LND was using on average. I believe that bitcoind was stressing it the most. I bought a 1 TB Sandisk Extreme USB SSD. I am still using it in my current build (I didn't want to spend any extra money on another internal drive) and it seems to be working as well as other SATA SSDs.
I also tried running ElectrumX on the Pi but I couldn't stand the noise of the fan which started kicking in even more frequently.