{
    "aliases": {
        "minecraft:overworld": {
            "dimension_types": [
                "minecraft:overworld",
                "minecraft:overworld_caves",
                "customdimensiontype:overworld_mirror"
            ],
            "dimensions": [
                "customdimension:overworld_mirror"
            ]
        },
        "minecraft:the_nether": {
            "dimension_types": [
                "minecraft:the_nether",
                "customdimensiontype:the_nether_mirror"
            ],
            "dimensions": [
                "customdimension:the_nether_mirror"
            ]
        },
        "minecraft:the_end": {
            "dimension_types": [
                "minecraft:the_end",
                "customdimensiontype:the_end_mirror"
            ],
            "dimensions": [
                "customdimension:the_end_mirror"
            ]
        },
        "customdimension:dimension": {
            "dimension_types": [
                "customdimensiontype:dimension_mirror"
            ],
            "dimensions": [
                "customdimension:dimension_mirror"
            ]
        }
    },
    "tweaks": {
        "customdimension:dimension": {
            "fix_sleeping": true,
            "fix_portal_search_radius": true
        }
    }
}

Aliases

In your datapack, create "dimensionfixer" folder with "alias" folder inside. In alias folder create json file with your dimension name with content:

{
    "dimension_types": [
        "test:one"
    ],
    "dimensions": []
}

Tweaks

In your datapack, create "dimensionfixer" folder with "tweak" folder inside. In tweak folder create json file with your dimension name with content:

{
    "fix_sleeping": true,
    "fix_portal_search_radius": true
}