I'm aware that I could flash a new ROM, and for security reasons that would probably be a good idea. However, I haven't had an OS update in 4+ years and I like how everything works right now.

I can assure you that all the apps that I listed can be fully shut down without impacting stability. Contacts and Phone are probably there so receiving a call is fast, which is fine, but atfwd is only used for screen mirroring which I haven't done in years, and DeX is for Desktop-ifying your phone, which I've never used and didn't even know existed. These apps have no business being loaded all the time, even if they're just libraries. Messenger isn't even a system app, why is it allowed to start itself at all?

Services on the other hand, are usually much lighter and also more hidden. To even see them you need to enable dev options, and this is where things can start breaking. This is where google Play Services and some system processes are located, as well as the home screen service and keyboard service. Even here there are 2 smart home processes which I've never used, as well as an iris scanner I've never enabled.

Most of this is besides the point anyway, which is that system apps can be just as guilty of hogging resources as any poorly made app short of a miner. Even the Android OS is hella bloated, taking a full third of this flagship phone's RAM at all times, and 6GB of storage. That's nearly desktop sized resorces. If someone uses more common apps than I do regularly or don't bother to disable bloatware, I'd bet this list would be much worse.