I read it years ago (though I was never a Tintin devotee, I was a fan) and when we were shopping at a children’s bookstore in Baltimore, it was one of the books I picked up (knowing that I would get a chance to read it before giving it away).
Tintin in Tibet is considered a bit of a turning point in the series, marking when they started becoming something worthy of classic status. And it is fun, exciting and a wonderful read for children.
Tintin in Tibet is less problematic than many of the Tintin books, but it is not not problematic. He manages to avoid too much racism, but it’s all, definitely, pre-postcolonial. Which is to say there is not so much overt racism, as implicit Eurocentrism, Euro-superiority. But the adventure is inspired by rescue Tintin’s friend Chang (Chinese, as you can imagine), who is treated almost as an equal. The Tibetan monks are depicted respectfully. The main issue are the guides, the sherpas and other forms of help. Their depiction can be a bit of a caricature of primitive exoticism; which is to say, they are too servile, too childlike, and never really equal in agency and intelligence to the white characters.
Also, as an adult, it’s hard not to read this and be very concerned that the Captain has a serious drinking problem. Very serious. It’s disturbing, rather than funny.
Tangentially related, the Belgian government sponsors a Tintin store in Singapore (in a touristy section of Chinatown). We visited it. I wish that I could find the picture of it for you, but that’s life. It’s full of disappointments.