It’s a SMR drive, thus - slow. See PSA: Beware of HDD manufacturers submarining SMR technology in HDD's without any public mention
The external drive is not a good solution anyway - they can detaching during the high load or be disconnected because overheat of USB controller. Without additional power supply they can disconnects too.
There is no good solution for SMR disks, they are known as bad for random writes (99% of all writes in storagenode). The workaround is to distribute the load by running more than one node on different drives in the same network.
Regarding database, you can move them to the SSD: