I scratched the yo itch in so far as I owned one and it was lovely. It had suffered the same issue as yours (seat tube) but the rest was sound. Previous owner had a repair done, replaced the full seat tube. However this is where I kind of fell out with it as there were a couple of issues with the repair I didn't like.
1. Seat tube was no longer the proper yo size, 27.2 not 29.4.
2. It was fillet brazed not tig welded.
I could live with 1, it opened up seat tube options, bit 2 annoyed me aesthetically.
I may have kept it but it turned out too small.
I guess I'm saying that you may find that it is only the usual BB area issue caused by no drain holes and water pooling as a result. If you plan to restore it and repair anyway, dig further economically before you put any significant time or money into it
Aside from perhaps cost saving, I've never understood why the most common fix is a sleeved repair when you could replace the whole tube. I've watched a few repair videos and the level of effort to do it can't be too far off a full tube replacement
I'd still like another one day, one I can ride. Good luck with yours, I hope it is sound everywhere else.