Hello,
Up front, let me say that I’ve never used S3-based storage, but it’s something that’s been on my list for a while. Proxmox Backup Server 4 is coming, and it will be able to back up to an S3-based storage target. Seems like now is a good time to start exploring in-LAN S3. 
I’d been planning to use MinIO, but I noticed that there’s apparently been/is going to be a fork for Open Source Project Reasons (@kris and @HoneyBadger talked about it on the podcast).
(I’m being deliberately vague because I don’t want to get mired in whatever is going on inside the MinIO project … or isn’t going on.)
So, let me ask the question like this: For someone who’s never used S3-based storage, but wants to set it up on TrueNAS for local, in-LAN use, what’s the best way to get started and actually learn what’s happening (as opposed to setting up something complex using a guide and having no idea how it works at the end)?
Any YouTube videos or guides I could read would be greatly appreciated. I’m sure I’m not the first person who’s wanted to get started with this.
Thanks!