stableheapbtreemap is a BTree (sorted map) that is efficient for key sorted data, as all operations are O(logn). We’ve been using it in production with CycleOps for almost two years, and for building secondary search indexes on several other ICP apps as well.
FYI filtering isn’t ever efficient unless you create indices for your data.
So if you have a large enough dataset, you’ll need to plan out your data model to support efficient indexes queries.