Cro is a rather large package intended to run full blown interactive services multi-threaded. So that does not seem out of place.
However, the amount of memory "used", may actually be a lot less in reality. For instance, if a run:
$ raku -e 'say Hello World"; sleep'
on MacOS with an M1, Activity Monitor reports that as using 82.4MB. But if I let the system itself report what its max_rss was for a process, it reports as 140KB. So I'm not sure if the MB number indicate actual memory usage, or just potential usage.