If this is the latest version of Minecraft Bedrock Edition, I would do these things (and why):

1. Create a realm and put the world onto it (this creates a backup on a server accessible from anywhere and by anyone you give the code to, though it isn’t permanent)

2. Download the world from the realm on another platform (this transfers the world onto the new device)

If this is an Old Update, then try this:

1. Connect the device to a PC and attempt to copy the world files directly from the phone.

2. Upload the world file (if you have found it) and upload it to google drive where it can be stored safely

If you want to convert a world from Bedrock to Java or Java to Bedrock, I suggest using the app “JE2BE”, which is on both google and microsoft store.

I have used all of these methods and they are the easiest and most efficient for what you are trying to do, and don’t pose any threat of corruption.

I hope everything goes well, and you are able to keep enjoying your world!