Here is my attempt to archive r/homelab before it went dark.
Google says there about 92,400 results for site:reddit.com/r/homelab, I have 2098, that's only about 2% of it. Maybe there is something of use to you in that 2%.
Also as many people come to r/homelab via Google, putting cache: before the https:// in chrome will yield the google cached page, which doesn't go to reddits servers. Also to be clear the mods of r/homelab have no intention of nuking the sub and losing any existing data but appreciate the efforts being made by users and r/datahoarder.
it's not official, also the mod here seems to be inactive. but it's the biggest homelab lemmy I could find on https://browse.feddit.de/
I don't know where all the people from r/homelab have gone. some other subreddit that have closed have flooded into lemmy but r/homelab doesn't seem to have done that.
A lot are on discord, but the mods are looking at an official Lemmy alternative. At the moment lemmy.ml is having significant issues so I'm not sure how that's impacting federation, but hopefully they improve their servers soon..
Personally I don't think Lemmy is really a great alternative in its current state especially with servers being able to defederate other servers, meaning that users registered on Beehaw for example can't now view communities hosted on lemmy.world which seems to entirely defeat the purpose to me..