Updating MacOS means I have to spend weeks:
1. Finding third-party utilities to replace what Apple took away.
2. Finding ways to disable the shiny new things Apple added that get in my way and are not officially turn-offable.
3. Finding workarounds for new bugs Apple introduced.
And recently,
4. Disabling all the new phone-home daemons Apple added.
MacOS has become a shitshow.
I didn't use any icloud stuff and was kinda shocked how much the OS called the mothership after installing little snitch ... Never properly gotten into finding what every daemon does and if I could disable it.
I typically have to spend some time bisecting this script to keep the few services I need (e.g. Messages) running. It's time-consuming because some services depend on others that have different names, so it's not as straightforward as simply re-enabling every daemon that contains the string "message."
Little Snitch [1] is also quite useful; it's probably easier to install LS with everything disabled and then gradually reenable the daemons you want. I use LS more than I use the above script these days...although LS still allows the daemons to run and consume CPU time, which the script stops. Probably best to use some combination of both approaches, and keep track of any edits you make to the script because Apple will likely reenable everything the next time you upgrade MacOS.
[0] https://gist.github.com/pwnsdx/1217727ca57de2dd2a372afdd7a0f...