Most likely you have a very old version of java installed on your machine and curseforge is using it because it is the java in your operating system path .
This comes up multiple times a week in relation to the Forge installer. e.g.
If that doesn't fix it, you will need to speak to curseforge: https://support.curseforge.com/en/support/home
If you have a dimension then you must have a chunk generator and that must have a biome source.
The biome source is what decides which biomes to use.
You can do all this with json as well if you want: https://minecraft.fandom.com/wiki/Custom_dimension
You only need to write code if the vanilla options/behaviour are not what you want.
After doing what you said ealier using curseforge launcher it says this
Failed to download file.
Error details: schannel: failed to receive handshake, SSL/TLS connection failed
Filename on disk: forge-41.1.0.jar