I dislike JS just as much as the next guy but the only real contender on the list is Qt. Which you need to license for commercial development. Furthermore, even though I like to think that I'm ok in C++, I would really think twice before using it on my next project these days. The JS performance issues should go away for the most part when wasm is standard. Also a lot of people write some compile to JS language, not…
Or is the cost of the license really that prohibitive for a well supported and performant piece of software?
[EDIT]: I found the pricing after a bit of creative googling: Startups is about $1,000 a year, non-startups are about $3,500 a year. Even without the discount, that's roughly equivalent to a month of one developer's time. IMO, not a terrible deal, for something you can freely license and use for cross platform development.