Why do F1 engineers prefer short stroke engines with big bores instead of vice versa or square?

Because the rod to stroke ratio is higher, so there is less rotating mass, so you can have sky high redlines, because the crank and conrods won’t bend or flex.

With short stroke an engine can reach high rpm easily, so it has a lot of hp but a little torque (like the N/A F1). I think that a F1 car doesn’t need big torque because it is very light, so, in modern turbo F1, where a big part of torque is generated by the turbo, is preferable a short stroke engine. This is my idea, but I can go wrong, hope that I help you