I wouldn’t rely on the thief not knowing how to read linux partitions. That very well may be the case, but the person they sell your hardware to will know better, considering they are in the market of purchasing used server hardware.

I self host and my threat model is the thief selling my server to someone who knows what to do with it, but not knowing how to extract encryption keys from the memory of a running server before unpluging it. That being said I haven’t figured out encryption yet so watching this thread.