Tapping to Ital and just leaving it like that is functionally fine, just a bit weird to have Ital thread and only 68 mm wide. Ital BBs are made for 70 mm shell width.

Another option is tap to Italian then use an Ital-Eng thread adaptor. If the thread is only bad on one side, you only need that one side done. Though if going from Swiss, I'd do both sides, so they can both be English/ISO. Having one side be Eng. and the other Metric could cause a future mechanic some excess stomach acid.

I have a set of those thread adaptors, they're a marvel of machining, Eng on the inside and Ital on the outside. The right side cup is left-hand thread on the inside, RHT on the outside. Got them from Ceeway in the UK.

They can be permanently loctited in place and then the frame is pretty much good as new, except Eng/ISO thread.

I also have the reamer and Ital taps to do this repair, in case anyone in the Seattle area needs it done. I'm not soliciting out of town work though, don't love the hassle of boxing and shipping. But if you bring it to me, I'll do it while you wait.

Theoretically, I could also make adapter rings to go from Ital to Swiss (or French). My lathe can make those threads, but it would be a very expensive repair. I am an inefficient amateur machinist, everything lakes me 3x as long as it would take a real machinist. I have made some pretty nice threads though. I might make French or Swiss adaptor rings someday, for a bike for me, as a hobby. Just to prove that I could do it. But if you had to pay me, it'd be too expensive, for most bikes. Well, maybe for some priceless holy grail frame. Hmm, if you have something like that, we can talk. Even then though, someone with a CNC (like Jim Merz) could knock out a pair in a fraction of how long it would take me.