I also
have around 10 TB of external USB disk space but I guess that is nothing I can
use to speed things up

I
could re-install the SSD and get one more SSD for cache, but there are no disk
connectors for any more HDDs so one of the other above would need to be removed
;-(
Then it’s a question what generation of SSD to get, would a 120 GB be
enough for cache or 240?
Anders