You can save your worlds in the Files app. Go to On My i[device]/Minecraft/games/com.mojang/minecraftWorlds and move the folder containing the world to your iCloud Drive or onto the On My i[device] folder.
I do not have any solution to the crashing problem though.
hey, so i made the pack like 5 months ago, and so i forgot to change the uuids, sorry about that. my only fix is to delete it from the realm's files. havent touched my pack in a while and im sorry for any disturbances i may have caused if you have this problem. i am currently trying to find the actual source of this, cause a old (bad) friend of mine put the pack into his realm and it broke, which possibly spread through their network. mind you, that bad friend is a hacker and shouldnt be trusted.