Worlds won't load to Realm Server on Switch Edition

I've paid for the Realms subscription on my Nintendo Switch more than about I'd like to say 4 months ago and I haven't been able to add my current worlds onto a Realm's Server. I've seen this issue and I originally thought it was an issue with the world size but it isn't my world size at the time was about 20 mb but now it is 70 mb. Everytime I try and upload a world no matter the size it says "Error" or "Upload Error" I wanna do this so only my friend and I can play the world but I feel like I've had my money taken from me at this point. I've also bought Windows 10 edition and this is supposedly the only way to transfer worlds over but I don't know what to do at this point. What is the fix to this issue?