Your call. You have to do what is best for you, and what you are most comfortable with. Nobody here would bust your chops if you wanted to turn it into a boat anchor or a shop stool.

Obviously, the best solution would be to pull the downtube out and replace it - which would be cost-effective if the frame were made by Colnago, Cinelli, Tommasini, Spectrum, Hetchins, etc. That solution would also cost a crap-ton of money

Out of curiosity, are you going to try for a refund?