World size customization

I used to be a legacy addition player and my favorite thing was creating worlds of different sizes. I think it’s kind of unfair that we only have 256 and infinite sizes. I understand that bedrock is a bit more spread out so there would be complications with the nether and end but I do not care.
Maybe after 5000 block maps we could have access to these dimensions.
This would really make pvp worlds more fun because it is frustrating when my friends run 100,000 blocks away

I would suggest that this would be achieved by making a slider that allows you to control dimensions of worlds from 256-100,000 and then infinite