Couple things to think about.

Is the CPU supported? Anything 32 bit is pretty well done in the computing world.

Why do you need caddy and SSL? Unless you plan to expose it directly to the internet which is a risk in and of itself is not needed. A cloudflare tunnel or VPN connection will give you access if needed with less exposure and risk.

An SSD is great for speed but your going to spend twice as much for the same amount of storage and in most situations a hdd will work fine. So unless you intend to really do some thrashing on the storage with demanding high speed reads/writes or lots of read write operations you will have the ability to put in more storage for the same cost.

Be wary of using USB drives to extend your storage. I’ve seen people do it and then deal with hassles and data loss. If you need more storage at some point build a NAS from a used server. My server is mostly used parts and has worked great. External drives are fine for offline backups.