Redmi 13c has gorilla glass
The display is basic 720p (12 has 1080p)
12 also has a ultrawide camera too but I don't think it'll be used much so go for 13c
for basic social media and calling 720p displays are good too, give better performance in games & efficient in battery backup.
Also MIUI has ads so when setting it up, uncheck everything that says recommendations and then go to settings of each system app (file manager, music and video player, security app etc and turn off recommendations)