Ok, next test completed.
I built with the following plugins:
https://github.com/discourse/docker_manager.git
https://github.com/discourse/discourse-data-explorer
https://github.com/communiteq/discourse-legal-compliance
https://github.com/pfaffman/discourse-allow-pm-to-staff
https://github.com/singerscreations/discourse-stopforumspam
https://github.com/discourse/discourse-cakeday
Swap was disabled, so only 4GiB/3.8GB RAM.
Maximum memory usage during build was 3.4GB. Build time was 6m 48s.