Try running Elasticsearch + Filebeat rather than the full ELK stack for a more lightweight approach. Ingest pipelines negate most of the need for Logstash and Kibana can be spun up when needed. You can also change the processors config option to make Elasticsearch reduce the processors it uses. NB I work at Elastic.
Great work. A lot of these optimisations seem to be suprisingly low-hanging fruit. I would have assumed that Array.unshift would already be optimised to not be O(n). It probably implies there are many such opportunities in the lower level stacks in browser and UI frameworks.