I have searched and searched for an answer to this issue but am unable to find it. I have checked the boot thread on the main forums but with no luck.
I got a new 3B+, formatted an SDCard using Raspberry Pi imager from the website and wrote Raspberry Pi OS. The first time I did this it booted fine except for a power issue (faulty USB port). Changed the port and everything was good.
(To expand the power issue is fixed, I have the official plug adapter for Raspberry Pi so use that as well, same issue.)
Took the Pi home and then it wouldn't reboot, so I re-wrote the card, got a new card and wrote that tried several times and it booted once but then errored out, tried several more times and still nothing. Just a constant red light, the other light doesn't change.
Now, if I take said SD Card, put it in a USB to SD Card "reader"/"converter" and plug that into the Raspberry Pi, it will boot from USB.
Does this mean my SD Card port on the Raspberry Pi 3B+ is broken...am I missing something? I searched but couldn't find any similar issues.