convert_input_source_to_en_karabiner.json

{
    "description": "Convert to en when ESC",
    "manipulators": [
        {
            "from": {
                "key_code": "escape",
                "modifiers": { "optional": ["any"] }
            },
            "to": [
                {
                    "key_code": "escape",
                    "modifiers": []
                }
            ],
            "to_after_key_up": [
                { "select_input_source": { "language": "en" } },
                { "key_code": "escape" }
            ],
            "type": "basic"
        }
    ]
}

Karabiner-Elements Settings -> Complex Modifications -> Add your own rule