if you're only using node-steamcommunity, I don't think you need much ram but for rate limit, YMMV.
I used to run 50 accounts, 10 of which has a steam-tradeoffer-manager instance and the rest only steam-user and steamcommunity, running in less than 500mb.
Fetches inventory every 10 minutes for all initiated accounts,
Fetches boosterpack catalog every 10 minutes for all initiated accounts,
Fetches badge data (1 every 30 secs)
Internal stock balancing.
Not using any proxy.
Nodejs, pm2, ASF, nginx in a 1gb droplet.