Amulet-Map-Editor VS Geyser

Edit: AmuletEditor: https://www.amuletmc.com/ Plugin to edit NBT: https://github.com/PREMIEREHELL/Amulet-Plugins/blob/main/EntitiePlugin_nbt_edit.py

There were a few projects that continued working on it. One of them, “MCEdit: Unified”, was supported until 2019, but I don’t believe it supported the MC 1.13 Block ID formats. The team remade it for newer versions and named it Amulet for MC 1.12+.

You can use Amulet to delete chunks that you don't want, and it seems to work with both Java and Bedrock worlds.

Try exporting your map then using Chunker to convert to .mcworld. If your world size is too big for it, try Amulet Editor. instead.

Use a map editor like Amulet to delete unused chunks of the map.

I’m not too experienced with it, but you can try to use amulet to try and edit the nether chunks

https://www.amuletmc.com It's pretty easy to use and it does offer the option to change biomes for selected chunks, as well as trim worlds etc.

If you have that, you can use Amulet to copy the chunks to a new world. Amulet also offers a feature that might be a better option for you. It will let you select chunks to save, then delete all others. This lets them regenerate with the new features included.

MCEdit is not compatible with worlds newer than 1.12.2. Some of the developers moved on to Amulet, though I'm not sure how feature complete it is.

There's a mod for Java servers that allows Bedrock players to join as well. https://github.com/GeyserMC/Geyser

Geyser: Download Geyser

Geyser is a plugin that you can install on your server to enable crossplay. You can download it from their official website or from their GitHub page. There are different versions of Geyser for different types of servers, such as Spigot, Paper, BungeeCord, Waterfall and more. Make sure you download the version that matches your server type.

She plays bedrock edition on her iPad. MacOS only supports Java edition. You need something like Geyser to play together or use software like Parallels to install windows on your Mac so you can play bedrock.

geysermc is a plugin that allows bedrock players to connect to Java servers https://geysermc.org/

In case you're willing to give it a shot, see: https://geysermc.org/

Its a plugin called GeyserMC that lets Bedrock players join Java servers.

Geyser: Geyser is a proxy that lets Bedrock Edition players join Java Edition servers. It supports most Java features and cross-play between different platforms. You can use it as a plugin or standalone proxy. You can download Geyser from here and join their Discord for support here.