Can't speak for OP, but such accuracy numbers often hide a 20/20 hindsight bias. After having built and run a rule-based system for a while, you always get tre

Can't speak for OP, but such accuracy numbers often hide a 20/20 hindsight bias. After having built and run a rule-based system for a while, you always get tremendous subject matter expertise, a feel for what works. Any rewrite of the system at that point will lead to much improved accuracy. The clarity is reflected in a better choice of the input signals, features, data preprocessing, metrics, workflows… A "magic ML" (without domain understanding) beating well-tuned SME rules is a dangerous fantasy, in any non-trivial endeavour. In other words, without that clarity, you're better off gaining it first through simple iterations of rules, figuring out what matters.