Hi,
I wanted to change the prefix (color) of the player when he enters another world, and so that everyone could see it, but I didn't understand how to do it. Is it possible to do it at all, and if so, how?

The only way that come into my mind is to create a different group with a specified permission and giving this permission to the player whose world has been changed.

In LuckPerms possible with context https://luckperms.net/wiki/Context

I tried to do it, but it seems to me that I'm stupid enough and I don't understand how to do it.

Hello again.
In TabList's groups.yml file create multiple groups like this, in each one change what you want (prefix, suffix) and the permission, which will define what world this will be displayed in. We'll create it for group Developer in this example.

groups:
  developer-world:
    prefix: '&aDEVELOPER '
    tabname: ''
    suffix: ''
    permission: tablist.g.developer-world
  developer-nether:
    prefix: '&cDEVELOPER '
    tabname: ''
    suffix: ''
    permission: tablist.g.developer-nether
  developer-end:
    prefix: '&dDEVELOPER '
    tabname: ''
    suffix: ''
    permission: tablist.g.developer-end

Then in LuckPerms Developer group add those permissions like this, with the context of whatever world name you want.

In case the player in this group is opped, just add this with value false

Now the prefix for players in Developer group will change depending on what world they're in. Good luck!

I definitely should have guessed it earlier, everything worked out, thanks!