Just to update and cross link macroBody conversion for Connect Cloud to Forge Cloud see
=> Support for saved macro modules when migrating from Connect to Forge macro - EAP - #5 by HanjooSong
TL:DR: Storage format will be converted and the good old plain-text macro-body will be available via forge config __bodyContent
// Forge
const config = useConfig();
config.__bodyContent;
BUT: Only for Connect Cloud to Forge Cloud migration
Server/DC to Forge Cloud migration is NOT COVERED as of 2022-09
Maybe another Atlassian Team in charge of Server/DC can jump in and deliver this missing piece 
I am looking forward to it.
Cheers,
Bernhard