The webui “can” be changed to support running shell scripts, but it is unlikely to receive the coding effort required to develop and test it.
There’s almost always still a way for the servers to be run entirely within the existing functionality of mineos, as many people run forgeloader already (and merely adapt the configuration to match the sh script).
Take a look at this here for how to change an individual server to use the Java binary of your choice:
Then, see what other arguments forge tries to add, and put them into the webui via xmx, xms, and the additional parameters input.