How do I access an encrypted SSD through Samba/Dolphin?

You cannot - at least I don’t think you can - encryption is usually to ensure data is safe and making them available through a network share is not safe.

If you absolutely must - in a controlled environment - and as you state - both systems run Manjaro - I suggest you use NFS and static IP addressing inside your controlled network.

You can get an idea on how to achieve this by reading reading this topic