The factory fitted screen guard is a thin plastic film usually in most phones, maybe that was the case here. Plastic film is not durable and won't protect from scratches if you use it for a long time. That is why I always buy a tempered glass screen guard whenever I get a new phone. My old OnePlus 3T, 6T and 7T all still have their screens new and without a scratch like day 1. Got a new screen guard for my S22+ too when I got the phone.
I wasn't expecting it to protect, but the claims of gorilla glass 5 are in question. I am not a fan of tempered glass as it diminishes the Amoled viewing experience.
Buy good quality tempered glass such as from Spigen. They're so thin you'll not even notice you have a screen guard in there. As for gg5, I never trust these so called toughened glasses so I put my trust in my screen guards, especially when the display replacement in high end phones can cost a lot of money if broken or cracked.
Tbh I never believed that tampered glass would have saved the phone screen from the crack. It's just something I feel is a waste of money but gg5 and ceramic shield of apple,I also agree with you on that
