I run a full node on Rapi3+.
I followed Stadicus Guide and translated it in Italian (in signature) to help other running their own node.
For a series of mishaps my block.dat got corrupted, so I had the blockchain download in my SSD and I had the Raspi to validate it.
It took more than a month to fully validate the blockchain back in february.
Of course this is not what it is meant to be, but of course improved CPU performance and RAM are a more than welcome upgrade in this case.
So I second OP request to know more on validating/syncing blockcahin.
Re:SSD, in my experience they are not meant to be used as a constant R/W devices like an hard disk, so I have been told their use as mass storage is not optimal and quite prone to errors and data corruption.
Waiting a little bit to put my hands on a Raspi4 because of I heard of a few minor design flaws in the board.
https://arstechnica.com/gadgets/2019/07/raspberry-pi-4-uses-incorrect-usb-c-design-wont-work-with-some-chargers/Nothing too relevant,. but waiting they get rid of their stocks and design a new board version.