Not sure what to do with 14 RPis at all. What is the point to have them 14? Computing power? How many ppl will do this?
So maybe I'm ignorant but how easy is to manage some application (or write one) to distribute its own workload to multiple machines when this task is sometimes a struggle within a single machine? And how about storage and dozen of other aspects?
Better then building 14-RPis rack (for example from RPi4 with 4GB RAM, decent SD cards, 14x PSU or one big, fans, filament for the case) ... cca $1000 ... one shall buy a decent server from ebay/Craiglist/etc or buy some tiny desktop with Ryzen (i.e. Ryzen 5 Pro 3400GE ... whole machine can "eat" around avg. 10W) for a half price.
I think this is too small for the Guiness record and too much for anything reasonable.