I went from 2Gb swap to +8 in an additional swap file for a total of 10Gb.
It's been running a few hours now and RAM usage is up to 5Gb out of 8 now, from 3.2-ish originally, and swap usage down to 1.6Gb from 2 originally.
Swappiness down to 0 now from 60 originally.
However, Bitcoin Core doesn't show any improvement 🤷🏻♂️