Doing this, running on a VPS with 1GB of RAM perfectly fine. No whitelisting required but you will have to manually subscribe to everything you want to see, so such thing as a proper “all” feed since this only shows feeds that users of your instance are subscribed to. Subscriptions are a bit weird, you want to search for the full URL of a sublemmy, then try it again after some minutes for it to work since it has to be fetched first. The ansible playbook is ridiculously easy to use for deployment.
Mastodon is a different beast, from what I saw so far, this needs much more configuration effort for deployment.