custom_mc_advancements/data/canopy/advancements/end.json

{
	"display": {
		"icon": {
			"item": "minecraft:end_portal_frame"
		},
		"title": "The End.",
		"description": "That was easy.",
		"frame": "task",
		"show_toast": false,
		"announce_to_chat": false
	},
	"parent": "canopy:root",
	"criteria": {
		"reach_the_end": {
			"trigger": "minecraft:location",
			"conditions": {
				"player": [{
						"condition": "minecraft:entity_properties",
						"entity": "this",
						"predicate": {
							"location": {
								"dimension": "minecraft:the_end"
							}
						}
					},
					{
						"condition": "minecraft:inverted",
						"term": {
							"condition": "minecraft:entity_properties",
							"entity": "this",
							"predicate": {
								"type_specific": {
									"type": "player",
									"gamemode": "spectator"
								}
							}
						}
					}
				]
			}
		}
	}
}