Make sure you place the card in the correct orientation when placing it into the tray. One corner of the card has a little angle piece missing in order for it to be placed properly into the tray. My Samsung phone I have to hold the card down in place in the tray while inserting it or for some reason it wants to push out of the tray.
You have a phone capable of eSIM so no the card isn't necessary. You might have to contact customer service to switch to eSIM but not sure. In the app find "switching to eSIM is simple".
