When I said 3rd party I meant non mojang jars, not hosting providors

Not when compared to the third party servers. Not only do they run better but they give the option of using plugins or mods to further improve performance and enhance gameplay.

Weekly full backup, nightly incremental

That’s how I do it. I tend to sort by hot because active doesn’t tend to update as often. Hot shows new content more often and I can filter out more communities I’m not interested in.

Llama does have some details on GitHub about this. According to them, no, it does not send data anywhere. You can also monitor network traffic to watch for it sending anything it shouldn’t. If you don’t want to do that, firewall it.

If you want to learn more, then you will need to move away from casa. Casa is pretty much just a collection of custom docker images that play well together and with their interface. You could grab an old computer, install Linux, and do more but you would expend more time and effort.

Didn’t uBlock origin just stop working with Chrome?