I’d say like most with 50k miles on an ‘18 is high! 12-15k is the average for vehicles in most cases. I personally would want more warranty coverage left, but you can buy an extended. At this price level and better APR’s for new loans may be the better option.
Or you can take the option one person has mentioned and buy a Tundra! I can’t see how this truck can be brought into the same conversation. But I would look at this truck as sort of on the boring side new and keeping it for 20 years? You would really be bored of it by then. I kept one truck 17 years and while it held up well, it wasn’t anything exciting to drive and was long dated. But you know what you want and like.
Just do your homework and asking around helps.