There are self-hosted Forths

Subleq and Eforth can self-compile, yes.

Being base.dec a subleq EForth image and eforth.fth the source code, to create a new one:

       ./subleq base.dec < tuned_eforth.fth > new.dec

 And Uxn partially. You can run the compiler as a UXN rom (Drimflim.rom).