I've been wanting to give Fennel a try, currently I use Moonscript for my Lua transpilation
(https://moonscript.org/), but it has some criticisms and it can be a bit confusing sometimes.
There was s little discussion here ~18 months ago³, but it will feel largely circular if you look at it as people are suggesting fennel there ;)
¹ https://github.com/pigpigyyy/Yuescript
² This probably only matters if you have tonnes of moonscript, not just a little neovim/mpv/awesomewm config or something.