No, Raku isn't Perl. But it is high-level and offers quite a bit of 20/20 hindsight. The new constructs make it rather well suited to handling ETL, especially transforming bulky datasets. Finding duplicates in the nr.gz file is a multi-stage process, the first pre-processing stage can take hours. Going through a dozen iterations of the code I've found some alternatives for reading and parallelizing the data that could save re-inventing some wheels. Much of the linguistic territory here is foreign to Perl: gathers and takes, hypers, lazy operators, even the maps read backward (well, forward, but that's backward!).
Much of the programming involves tradeoffs between speed and size, as usual, so I'll also look at a few different ways to chunk and re-process the data for speed or space.