I would have expected some memory savings due to the indexes being lighter on the heap. Perhaps your workloads are more cpu heavy than memory?
https://underthehood.meltwater.com/blog/2022/11/25/how-we-up...
After those changes were made then we haven't had any major issues with heap spikes. But it depends on a lot of factors, how your data looks, how your queries look and what aggregations that are made so its very hard to give some always applicable advice.