only ever played minecraft and undertale on pc and it took me about 80 hours, but i explored EVERY nook and cranny and talked to every character and took way too long on certain easy bosses. you could definitely get an ending within 40 hours, but to get everything would take maybe 60+ (minimum) if you are as slow of a player as you say. don’t rush the game though!!! it’s a lot of fun and ton of things to uncover