How much pressure in removing SIM cards

Although the "pressure" is not clearly defined, Remove or switch the SIM card in your iPhone or iPad - Apple Support states:

To pop open the SIM tray, insert a paper clip or a SIM-eject tool into the hole beside the tray. Push in, towards the iPhone, but don’t force it. If you're having difficulty ejecting the SIM tray, take your device to your carrier or an Apple Store for help.

A lot of downward force.