Generally, a Samsung phone isn't great for privacy. Consider getting a Pixel and put GrapheneOS on it. Much better Android baseline. More secure as well.
Any connection to Samsung's servers is likely non-essential, but do check that OS updates work.
Google Play Services is Google's main surveillance stack on every commercial Android distribution. It transmits a lot of unique device info to Google, every 20 minutes or so. The minimum data being transmitted is:
Phone #
SIM #
IMEI (world-wide unique device ID)
S/N of your device
WIFI MAC address
Android ID
Mail Address of your logged in Google account
IP address
However, this app might be required for Google Play to function. And also for some other apps. So check those dependency issues. In general, you should prefer using open source apps or any apps which don't have such stupid dependencies. Some apps merely complain when you don't have the Play Services app running (by displaying a popup) but still work.
There's also the issue with Google's DRM called "Play Integrity". Some apps use Google's Play Integrity API to "verify" that the device is an "officially sanctioned Android" and then act like any other Android is "unsafe" and then refuse to work. If you encounter this, be sure to complain to the app developers about this.
If you need the Google Play store but want to block network access for the Play Services app (which you should do), you should probably use the third-party Aurora store app.
About the Ironfox connections: not sure, but the "firefox-settings" hosts from Mozilla sound related to the Firefox Sync feature which syncs your settings/bookmarks/... with Mozilla. If that's the case it's also non-essential and can be blocked.
