Problems

Turn your phone off,take out the sim card and whipe it gently and then turn your phone back on and see if it detects the sim card. If that don't work I'd try it in another phone to see if it works. I've had similar issue while back and it turned out I didn't insert it juuuust right.

As to the pin code,the fingerprint censor are bit sensitive i think and will do that sometimes.

Regarding the pin code question sometimes you're phone can hibernate when its in your pocket and the fingerprint reader can be temporarily disabled then it will ask for a pattern or a pin to open the screen after hibernation. It can also be that when its in your pocket it can sometimes light up the display a couple of times due to a sensitive powerbotton. And it automatically disable temporarely the fingerprint unlock so you have to enter your pin or pattern. Sometimes it can fix wake up the fingerprint unlock sensor again by pressing the powerbotton once more for an half of a sec. Regarding your sim issue it can be like my brother in arms @1855 describes here. Rarely a phone specific problem i believe its a simcard issue. But to be on the safe side i would recommend you to lift the issue with Samsung support for more accurate response to your problem. Bestregards AndroidSweden

I'm purdy sure you put the sim card in the wrong way 😆😂 . They are so small and the tray holding the simcard doesn't give much wiggleroom.