These days there are many games to go 2 after completing a game. There has to be more to offer for me to keep playing from the start.
Here are the things and games that made me replay in recent years:
1- Compact fun Gameplay
like Uncharted games 2-4, just pick the level and have fun playing in different ways. the post game shop let's you revers mirror the world and have OP guns. I replayed everyone of these 3 games more than once and still want to go back to them. Last of Us was less so because of resource grind and the slower nature of the gameplay. other examples are R&KPS5 and Vanquish.
Example of non shooters are NiOh1+2/FFO:SOP, tight levels with different strategies and fun combat with incredible depth and variety, best real time sword and magic system IMOO.
2- Alternate Story Path
Substantial amount of different narrative to experience. Resident Evil 2Re dose this great, Nier Automata did it even better, with different conversations and alternations in the world, good enough to get me over the the combat that got old.
Chrono Trigger still remains the gold standard for this element even after decades.
3- Rewards
Loot. Diablo and Borderlands are the obvious example and don't need explaining. My personal favorites are NiOh1+2/FFO:SOP. Most games unfortunately exploit the collection compulsion in a bad way.
4- Close Path to Platinum Trophy
By making most trophies achievable in playing the game fully and and being over-grindy and hiding a billion collectibles. If I find myself a few trophies away I do put time into getting them post ending. Sony games generally have the best measure in this
Hades has elements 1+2+3, insane replay value in that game. It's the best modern template for replay value.
NiOh1+2/FFO:SOP. have elements 1+3+4, if it had alternate story paths it would have had the complete formula.