Nutomic

Open all the windows during night time when its cool, close windows and shutters during daytime. If you dont have shutters, put foil on the outside of the window, not inside. Also use a fan for air flow.

You can follow Lemmy users from Mastodon etc. But the outbox isnt even used by Mastodon, so we havent bothered to implement it properly yet.

if i open my own user profile from mastodon, it only shows me about half the posts that i actually make.

That is normal, its usually because no one on that instance follows your user profile specifically. Part of your posts are federated because someone is following a subset of the communities where you are posting.

Private communities in Lemmy only federate with approved users and their instances. So if you dont trust lemmy.xyz, simply dont approve any followers from that instance, then it will never receive any private content.