Deduplication requires an absolutely enormous amount of memory, unless you have a dataset that has a huge amount of duplication for some reason (maybe a company or school where a lot of people have their own network storage and put the same large files in?) it is usually never the right choice to enable dedup.

It is cheaper to buy more disk than the memory to enable dedup (somebody could run the numbers). ZFS ARC also likes lots of memory and you get good performance gains with more memory allocated to it.

In other words, turn on LZ4 compression everywhere and don’t think about it otherwise.