One of the fastest bows I ever made was from fire-hardened Chinese elm sapling. I’ve got four fresh staves of it that are as straight as boards and really looking forward to them being dry!
I’m a huge fan of Hackberry. Similar in properties to elm. Light in physical mass, has no commercial value and takes over farms around here so it’s easy to get permission to cut as much as you want, and usually grows pipe-straight. With a good heat treatment it’s not difficult to get 165 fps out of good hackberry. With careful design and an aggressive treatment it’ll do 175 fps no sweat.
It’ll handle just about any design you throw at it. From Holmegaards to Ishi paddle bows to heavily-radiused longbows. Of course some designs are more “optimal” than others, but I’ve made a couple hundred bows with rounded at lenticular cross sections with it by now and they don’t disappoint.
If I was forced to choose only one wood to use for the rest of my life, it might just be hackberry.