RPis are great for a lot of projects, but sadly I have recently switched to other boards such as the Odroid XU4 giving the lack of Pis and the direction the company has been going. Still have my Pis which I’m going to use for a lot of different stuff, but man I miss pre covid times.
I’ve tested a 02 as the head node, but I’ve never been able to get enough of them to fully populate a cluster. 20 cores would help a lot, but the lack of RAM on the 02 will hold it back significantly