MacOS – How to manually control processes launched on start

Every time my Mac starts, about ~210 processes are launched, requiring about ~1000 OS Threads. With every Apple update this number increases. My laptop freezes for 1-3 min a couple of times per week because some process I've never heard of starts consuming 100% of CPU time till they likely crash. From googling process names the Apple process launch policy on laptops with limited battery life seems to be: launch every time everything for anything anyone might ever want to do.

• Is there a way to do something about this?

What I've found:

• Some of the processes are started by root (I don't want to do much about those).

• However, most of them are started by my user, and most of those are for things that I do not need or that I have explicitly disabled in system preferences (keychain, messenger…).

I guess launchd is in charge of starting all these processes. I've found /Library/LaunchAgents and /Library/LaunchDaemons but these are just a small fraction of the processes that get launched, and none of them are system processes.

• If they are all launched by launchd is there a configuration file for startup processes somewhere?

Note: I don't mind at all that a process gets launched when I do something that requires it. It is just that I find 200 processes, most of them for things I don't always need and a lot of them for things I've explicitly disabled, to be just nuts.

Update:

It seems that sudo launchctl list is a good place to start, one can then use launchctl load <service> and launchctl remove <service> to load/remove services. It would be nice to get a list of which services are safe to remove, and which services should never ever need to be removed, gonna experiment with that.