I thought i had a way to solve my storage problem when I got an sd card, I saw you could use an sd card as internal storage, so I tried it out, and it didn't work. I discovered later that Samsung had nuked the feature from all its phone( which was very disappointing.) I dont think they'll add soon because they removed the microsd from the s21, but I just wanted to say that. The sd card was my last solution and it doesn't work,so what do I do?
I don't think all my user data adds up to 15GB, I did the maths and it's only 4GB, so what's taking up all the storage?
I would store your your data in the cloud. I use Google drive associated with my email which gives 15GB free. I also use amazon prime which gives unlimited free photo storage if you are a prime member.
when you go into your storage settings click analyse storage. you might have a lot in the recycle bin. also go into my files an check internal storage. images and videos may be clogging up your storage