Best quality, design, finish & warranty support in Pop Up?

Know you’re dead set on the 150 but the same cab/bed config in a 3/4 ton would allow you to basically buy whatever you want.
That aside, one of my buddies put a lot of miles on an original tundra with a good size pop up in the back and no issues.
Your real world limiting factor is axle capacity, but I wouldn’t worry about putting a 2500lb plus camper on a new 9.75” ford rear end. She’ll hold up.