Hello: The other day (May 23, 2022), I took a picture with my fully updated and app updated Samsung S10+ the phone was held sideways as if you were watching a modern television/monitor while I took a picture. The photo came out as expected and upright. I sent the photo via Verizon Messenger and it showed up as being upside down on MY end. The receiver, the same. I went into photos and the phone was upright. I decided to flip the photo and save as such to see how Verizon messenger would receive it. It was still upside down on both sides, sender and receiver. I flipped it back, saved it as such, sent again. Upside down. Would love an answer to this. Thanks.
Try going to your Camera app > Settings icon > Format and advanced options > and switch HEIF format off. Let us know if this helped you.