Looks like S24U is a bit slow to sync. I have had similar problems too few days after I started to use the phone. When you transfer your data from your old phone to a new one, only the apps will be transferred but not the passwords. Make sure you are logged in and synced into all your apps again. Some will ask you to do this manually or the phone will ask you to do it manually or your Samsung or Google accounts. Sometimes you have to log in few times or every time you need to use it because some apps will log you out until you use them again. Some apps you will even have to uninstall and install again because they may be older versions.
The S24U is full of security settings hidden around the setting menus so make sure you have a look at those before you start using your phone heavily. Also check if your details are correct and updated on your apps profiles, sometimes this might be a reason why they don't work. My phone works fine except a few minor bugs but I am sure it will get better in time. Also the OS needs time to get used to your style of using the phone and then it will be more friendly.
Consider restarting your phone. It's the wonder medicine for every phone lol
