Hmm… I reviewed the linked thread and seems like since 2014 the multi-core and multi-container setup is still quite questionable (pains vs. gains) and very use-case dependent. Thanks anyway, I’ll keep it simple.
Some time ago I had time to configure multisite with 3 containers: data, web, and redis. All was working fine until one day I upgraded, and bam, something wrong happened and I had to revert to single site from backups.