Internal Speakers Option Missing

Hi,

Hoping for an easy fix, but not feeling too confident from the searches and options I've already tried.

The internal speakers option has been missing since December 2021 after my son used my Mac Book Pro (early 2015 version) on his school's sound board. He plugged in the headphone jack to connect it to the sound board and ever since then the internal speakers option is gone.

If I plug in headphones the sound works, it also works with airpods or other blue tooth devices and when I restart the computer I can hear the start-up chime.

There is a red light showing in the headphone port, not always but definitely after plugging in headphones).

I've tried plugging in the headphones and removing them to reset the switch inside many, many times. On occasion the Internal Speakers option pops up for a brief second when I remove the headphone jack only to disappear again.

I've restarted the computer and pressed control, option, P & R and waiting 20 seconds, I've also shut down and held control, option, shift. Not sure exactly what each of those are supposed to do but I read to try them in other responses to my same problem.

Removing the headphone jack and seeing the internal speakers option pop up for a second is the closest I have come to fixing this problem so I feel like that is where my ultimate fix will be but i just don't know what to do and don't want to spend a gazillion dollars fixing this old but well working machine.

If anyone has any other suggestions please send then my way. FYI - Im not in the dark with technology but I'm also not super savvy so please use layman terms! Thanks