Here are the main issues:

• Addons keep rearranging themselves. They are not in the same other as when I arranged them locally.
• World template addons (such as RealismCraft) randomly stops working after the realm restarts. This happens way, way too often. Sometimes it fixes itself. Sometimes it doesn't. I've tried disabling and re-enabling the addons, sometimes it fixes the issue, sometimes it doesn't. I've even tried to download the world backup, re-enable the addons, and re-uploaded it. Still the same issue, no matter what.
• Addons duplicating themselves, I don't know if this breaks anything, but from my experience, the duplcated ones are just... there. They appeared after a restart.
• Behavior pack is MISSING, BUT it still works in-game fine, as long as I enabled its dependency resource pack. It's just invisible or something.

Unrelated issue:

• Spawn Radius refuses to save, it works a bit, but as soon as the realm restarts, it goes back to the default value. Some of the Realm's world settings also behave the same.

I have had these issues pretty much since I started my realm. The most frustrating issue has got to be with world template addons randomly stop working. Very game-breaking, it made some of the addon's structures not load properly, many are cut in half as a result.

I've reached out to people on Discord and Reddit, many have the same issues I mentioned here. Players are losing interest in the realm we hosted because of the bugs.