hi! author of the Doom thing, here. while I won't be the one to try, my answer is "absolutely yes, it will make a massive difference". Sub-1-day Doom-first-frame is probably a possibility now, if not much more because actually the thing that was the largest bottleneck for Doom-in-TypeScript-types was serializing the type to a string, which may well be considerably more than 10x faster. Hopefully someone will try some day!
https://news.ycombinator.com/item?id=43184291
https://www.youtube.com/watch?v=0mCsluv5FXA